We had a spoons workshop at our festival a few years back: very good player and tutor. She did spend a considerable amount of time speaking about session etiquette, especially in relation to spoons and other percussion, including, "don't feel you have to play along with everything", and "one at a time only". Of course, later that afternoon, the pub session was full of people rattling away in all sorts of random rhythms. Fortunately most have disappeared without trace!

We do have a very good local player, who will sometimes play along with sets of reels or jigs, but only one or 2 sets out of the whole evening.

I confess now: I LOVE DRUMS OF ALL SORTS.(Some people equally hate them all with a vengeance.) But, I agree with those posters above who say it's OK to have SOME percussion, but not all the time, and knowing when not to play (never say never) - all in moderation, and know your tunes and rhythms. And DON'T launch yourself on the sessions until you CAN play in time and up to speed. On this one , I am in total agreement with GSS and Tootler, that it IS extremely useful to play along with CDs of jigs, marches and reels until you are sure you can keep up.
I did orchestral percussion and piano in my youth, which hopefully gave me a very good sense of rhythm, but does not necessarily prepare you for playing bodhran: it is NOT simply a matter of "thumping" (horrible expression), but learning how to control your drum and beater, get your upstroke as good as the downstroke, and use the hand behind the skin to vary the sound and tension.
I did 2 courses of daily workshops for a week each time, a year apart, so over 20 hours' tuition, then a lot of practice playing along with CDs, before I felt anywhere near ready to go into a session, and then, yes, sat in a corner and played quietly. Of course you learn from other musicians, but it's definitely not stage 1 in the learning process.