I know the legal answer to this question so that may well be the ethical answer as well.

You set your pal up in a stand a few hundred yards away from yours and you have 5 doe tags and he has none. You tell him if he whacks a doe you would be happy to throw a tag on it for him. You can have two deer down at the same time here so that would not be an issue.

They give out the tags to reduce the population of does so whats the big deal in the real world???