You don’t need the tool if you want to be devious. Just grab any readily accessible small piece of gravel, grit, or detritus readily available in any paved area and screw it down onto the valve pin with the tire stem cap. That’ll allow the air out of the tire and will usually fall out unnoticed when the mark removes the cap later. The problem will then not reoccur, but with luck they’ll be forever paranoid that it may randomly happen again.
You don’t need the tool if you want to be devious. Just grab any readily accessible small piece of gravel, grit, or detritus readily available in any paved area and screw it down onto the valve pin with the tire stem cap. That’ll allow the air out of the tire and will usually fall out unnoticed when the mark removes the cap later. The problem will then not reoccur, but with luck they’ll be forever paranoid that it may randomly happen again.