These are not true "explosive devices". They are merely failed pressure vessels. While they may seem like they are "explosive devices" because they make a bang and can cause some minimal damage, they are not true explosives.
While chemically speaking there is burning going on, it is a slow chemical oxidation. This slow oxidation allows these prank devices to be activated, sufficient time for them to placed, and sufficient time for the placer to remove themselves from the device. This is not an explosive.
Explosive devices burn at high rates of speed. The distinction between high and low explosives is the speed of burning. Black powder is an explosive, todays modern gun powders, as fast at they burn, ARE NOT explosives but PROPELLANTS.
The hubalo over these silly plastic bottles is nothing more than people trying to take simple pranks and turn them into federal cases. While damage and injury could occur by using one of these devices, they ARE NOT EXPLOSIVE DEVICES. They are vandalism when used to destroy property, they are potentially deadly (just as a gun used improperly has deadly potential), and as such, any damage or injury resulting from their use should be treated as a negligent or willful act and prosecuted under the underlying crime committed.
Calling these very common prank devices "explosive devices" is no different than calling an AR-15 an "assault rifle". Itis intended to mis represent the true nature of the item and build public support to criminalize them.