To do this would be a major nerf and a major buff in separate ways--it would be a nerf to the end-users who use epis for more than just aid for their teammates/friends, but it would protect a lot of random people from additional robbing/hassle/BS. That said, I don't think this should be done because I believe that in some ways it would restrict the roleplay opportunities, etc., that come from getting rev'd by a hostile team and having to deal with their demands/instructions to become their hostage or whatever the case may be. Obviously, there will always be dudes who use it to rev in redzones and then tap people so their guns are removed or whatever else people think of, but that's their prerogative and I don't think it should be taken away from them. If an enemy team really wants to send their money and epi-pen to revive you even after they've picked up your cases, then why regulate that?
Yes, but I would argue that that's part of the mechanic of epinephrine pens. I feel like the fact that you can be epi'd by an enemy balances it out. The epis are extremely powerful in that they can be used to revive anybody, anywhere, in any battlefield or situation, and I feel like adding the risk of, "Gosh, the enemy team might try and rev-rob me" is a cool and interesting twist on the item.
As I suggested in my first paragraph, it is my opinion that a rule like this would be regulating gameplay too strictly. 15 minutes is the same length as NLR, keep in mind--even the combat timer is only 5 minutes. In principal I oppose this because I wish the epi-pens can continue to be loosely controlled such as they are now. The most damage you can possibly do with one is kill somebody if they try and resist a robbery, that's my stance.