I went to play Lazer Tag with my Little today (my little brother from Big Brothers/Big Sisters) and IT WAS AWESOME!
Where we played, we had unlimited lives. You could get shot as many times as you wanted. All you had to do was wait 10 seconds, at which time you could re-position yourself, and you were good to go again. I loved watching the kids reaction to getting shot. They weren't deterred... at all!
Another lesson for us from the kids. When things aren't going as you planned, take your 10 seconds (or 10 hours, or 10 days) to re-group and re-position yourself. And get back in the game. Don't be deterred. Just keep playing!