Moving the button

[PiggSkin]

Forgive me if this has already been discussed...

Where can I find authoritative rules on how the button should be moved an blinds posted when people leave..? I've had a couple of situations where certain places have had strange rules, causing some strange incidents... For Example:

1) At a small casino in CA, the person on the button chose to sit out the hand... They then moved the button and made an additional person post the big blind... The following hand, the original "leaver" came back... They made her post a missed small blind... For that hand, five people were at the table and four posted blinds of some sort...

2) At a certain online site that really sucks but has the most fish, they move the button to the person on the right every time, regardless of who left and came in... Today I was playing and posted the big blind... The following hand, I expected to post the small blind, but ended up being the button... Apparently the person who just posted the small blind left, and instead of having a dead button, they made me the button... And the person who was to be the big blind was the small blind...

These both seem odd to me, and don't match what my limited experience tells me to be correct... Where can I find the authoritative rulings on this..?