Re Tango Victor's question, in the first group of which I was a member, just after purchase the aircraft promptly had a mechanical failure and a hefty resulting bill, mostly covered by insurance. It just so happened I was P1 at the time but the incident was evidentially not down to me; by consensus, we split both the excess and the uninsured cost.
The second group I was in, a group of friends, decided that we would not want to fall out about linking 'blame' with responsibility for the excess (we can all make mistakes, after all), so we decided to put in the bank, up front, a float to cover the insurance excess as well as some working capital. When the aeoplane was unfortunately written off, the unlucky member on this occasion accepted responsibility and, as a true gentleman and good friend, reimbursed the other members pro-rata for the loss of the remainder of the annual premium, and also covered the full excess.
I make no comment as to whether these two instances are typical of groups in general; I strongly recommend that rules are agreed and written before they're needed!
Slip