Very plausible. I also read where these guys would immediately open the cell phone boxes and put the batteries in a separate bucket, and maybe also set aside the smart chips. That doesn't seem like a way to preserve the detonator function once the batteries are out. I hope the NSA, FBI, CIA, ETC. are thinking about this.
#325, it makes sense if you get stopped with a trac phone with no battery/charger with you then you will not be held for suspicion on anything. You can have another partner in crime have a battery power pack in his carry-on luggage and then get together on the Plane. Remember that they are not letting people on these planes now with much of anything. Just thinking out loud right now about this,sometimes the little tidbits go a very long way to solving the big crimes.