Dear <confused>,
In thinking about your question, you brought me to an important question of my own. To whom does one report a PTO that is in violation of the by-laws? I know the chain of command for PTA from having attended many conferences where such issues are addressed, but because PTOs are individual groups, I wonder if there is any official channel for making a complaint without going so far as to risk having the group disbanded.
If you are friendly with the Board members, then you may be effective in dealing with these issues unofficially, by, perhaps, using just a little subterfuge (such as asking "Oh, I thought we would need to amend the bylaws before adding more Board members," etc.)or even bringing up your concerns to a Board member with whom you are friendly and whom you trust.) If all such efforts fail, however, then you are stuck with either A) Ignoring the violations or
Reporting the violations to the principal or higher, e.g. the IRS, which can revoke the 501c3 status if the bylaws are ignored. Only you can decide how important these issues are and how far you are willing to go to see that the organization works as it should.