I hope so. The point of these tools is that you can reach them while belted in tightly. In a collision or other accident, the seatbelt may tension and you may not have the freedom of movement you normally do. You want it where you can reach it, undo the velcro or whatever, and use it without having to unbuckle.
In certain hobby activities I sometimes participate in, we have to install an ABC fire extiguisher within reach of the belted driver. So it's similar. For maximum effectiveness, practice freeing it from the spot you mount it a few times.
You definitely don't want it to be flying around (possibly injuring you) and ending up out of reach in an accident.