Crazy Construction Conundrum

A while back, my family took a vacation to Gatlinburg, Tennessee for a family reunion / 50th Anniversary celebration for my inlaws.  It was a great time, beautiful in the mountains, lots of memories, lots of fun.  Having never stayed in the mountains before, it was quite the experience!  I could write and write and write about it; twenty people in the ginormous cabin, the game room, 5 people sleeping in my king bed, food, fun, fish.... 

But today I write about something on the drive home.  You see, we drove through Pigeon Forge to get to any sort of highway to get back home.  I remembered from our bumper-to-bumper ride IN that there was a construction zone, but hoped that leaving at 7am would alleviate some of the tourist traffic.  It did.  It also allowed for more sight-seeing on my part, since I was mainly focused on not hitting the bumper in front of me during the drive in. 

So as we near the construction zone, we see a sign: 

Kinda cool.  It allowed me time to think, "Wow... how awesome that they have to blast away a piece of mountain just to widen a roadway.  That must take a long time to approve a project like this one.  We are mainly concerned with filling potholes and laying asphalt as a quick fix in Michigan.  Imagine the meetings and planning that would go into this type of road project.  I say, it will be a nice road once this project is done.  Real nice." (There wasn't traffic, and the kids were still very quiet... got some nice thinking time in.)

Then a little further down, there was THIS sign:

Wait, what?  We passed it so quickly that there was hardly time for it to sink in.  I got a little panicky and thought of all of the electronics in my van running at the time.  My cell phone.  Jerry's cell phone.  Would the GPS be a problem? What about the DVD player?  Which do I start with?  Finding my purse to find my phone to shut it off?  How much time do I have??? 

Then - poof - we were through the construction zone.  I sat there confused.  I said, "Jer... did you see that sign?  The one that said 'Turn off cell phone'?"  He responded with an interested, "Hmmmm..." 

So now I'm a bit confused.  I'm still getting over the small panic attack. Glancing at the cars driving toward us - are they reaching for their cell phones? Looking in the mirrors at the cars behind us - no sign of anyone turning anything back on...  And I start to thinking...  scary, I know. 

This is a tourist town.  Tourist.  Not like small town, everybody knows everybody, the sign is just a reminder to everyone that already knows NOT to use the cell phone there... We're talking people from all over the United States who have never been there before.  One sign warning of imminent danger from something that no doubt everyone has in their car (I mean, even I have one...).  One sign!  One. Sign. 

So now I'm a bit flabbergasted.  There must be some sort of problem caused by having cell phones and 2-way radios in a blast zone.  Otherwise, why the sign?  Enter: my imagination...

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
(Work crew in blast zone, somewhere in Pigeon Forge, speaking in slight southern accent)
"Hey Bob, you got them explosives set up yet?"
"Crate just got in... I'm about to start settin' 'em now."
"Alright.  We just gotta get a move on before ..."

            KA-BOOM

"Dang it!!!!  That's the fourth time this WEEK that those charges blew before we could use 'em!  Who has their cell phone on? WHO??!!"
(Everyone shakes head, shrugging)
"Maybe someone drivin' by forgot, sir..." 
"Well, did you put up the sign?!?"
"Yeah, I put up the sign."
"You sure you put up the sign?"
"Yeah, I put up the sign.  Right by the road."
"You SURE you put up the sign?  'Cause these charges don't blow themselves up!"
"YEAH!  I PUT UP the SIGN!!!" 
....
"Hey Bob - put in 'nother order of them explosives..."

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

I thought, surely there is a different reason... Surely they wouldn't use a detonator that could be interrupted by something that everyone in their passing car would have on them... And if that really IS the reason for the sign - surely they would have more than ONE sign... Or another sign explaining the dangers... or an electromagnetic pulse like they use in robot movies to destroy the invading robots and save earth... Something....

Certainly that isn't the reason.  I searched it when I got home and found this conversation on Reddit:
Question: "Yesterday I drove through a construction zone that started with a sign saying "blast zone 1 mile", a quarter mile later a sign said "turn off two-way radios and cell phones"; can someone please explain how cell phones and two-way radios interfere with blasting sites? Also, since there was only a short distance between the warning and the site, what would the ramifications be if one does not turn their electronic equipment off in time" 

 (smart girl... glad I'm not the only one wondering...)

Answer: "Radio detonators could be set off by the signals from cell phones or radios, rare and unlikely but better safe than sorry when using explosives"
 
There has got to be a better way, right?  Please tell me that in all of our technological advancements, we have come up with a way to set off dynamite that a cell phone won't interfere with...  And if not,  maybe we go back to lighting a fuse?  That would be safer, no?


Although, I suppose any form of detonation has its dangers....