Q16. Can I play a Beer if I am at full life points?
A. Yes: the Beer will simply have no effect at all.
Good thing to know. On the flipside, if you are on Gary Looter's team, you can support Gary Looter fantastically by discarding cards that will help him when you are over your limit. So discard a Beer for Gary Looter to draw the card so he can regain health. The Sheriff-Deputy combo here is ridiculously OP.