[thanksforfish]

Agreement from me, although I'd avoid double booking. Double booking means that other people are expecting you to attend, they may wait to see if more people join, or need to reschedule if the right audience isn't able to make it. I think it's best to pro-actively reject meetings versus only showing up for one.

[mwigdahl]

Depends. If your schedule has a lot of flux (meetings being cancelled ad-hoc, etc.) then it can be useful to accept everything but notify the host that you probably won't be there unless something changes. That way if something does change you at least still have it on your calendar (I use Outlook, maybe other calendar/meeting apps handle this better).

[nraf]

Google Calendar has a Maybe option that solves it simply enough.