Exactly I find it ridiculous that it is Automatically checked for group liabilities, and I have seen even experienced SL users create a group and not check all the rights and permissions close enough.
So I personally think it is the creator or owner of the groups fault and have voiced it many times only to have other group members flair up about it being only 1 or 2L. Sure one group 1L - we can have 25 groups and if all group owners are nonce's that is 25L a week 100L a month and if you have left SL for an extended period of time 1200L a year or more. So it can add up, it does and if I join a group and then have money removed I IM the owner about it (nine times out of ten they didnt know it was doing that) and they stop the auto deductions, those that refuse or harp on about it - I remove. Groups arent that important to me - I can make my own tag if I want to.