I don't think it's that big a deal. If you're hosting a party, you're likely already shelling out for booze and food and such anyway, so spending an extra $10 so your guests don't get tickets seems worth it, to me. I just ask people to consider that I only have x amount of passes and that I'd like to have them available for people who can't carpool or take public transit in. And like I commented below, it's usually not much of a problem since people who live in the area understand the PITA parking situation.