tipping

You can't. She did it. You saw it. Either confront her with it or forget it. Looks like you'll do neither and just ruminate on it.

Our first experience of tipping in the USA.
We went into a restaurant in San Francisco the waiter came up to us before we had even sat down and said
"you guys do know that a 20% tip at least is expected for services in the US"
We walked out.
You are expected to give at least 10% even when the service is terrible.

It’s unfair to make this judgement about one of your sisters without giving her the opportunity to explain herself. I can’t imagine anyone having the barefaced cheek to steal money directly in front of other people.
Your daughter thinks she saw your sister take money out of the tip. Are you quite sure your sister wasn’t just changing money?
Do you know how much everyone contributed and what the total was?
Unless you know the answers to these questions you could be making a big mistake.

jeannie tipping at 20% is the norm in the USA. Sales tax on restaurant bills varies from state to state but is usually less than 10%. Compare this to the UK where VAT on restaurant meals is 20%.
We have travelled a lot in the US and generally find that for comparable quality, restaurant meals in the USA are cheaper than in the UK.
This is one reason we are happy to pay a 20% tip. The other reason is that generally we find the service is better in restaurants in the USA than in the UK.

Well according my daughter who was watching it all since she thought it was odd for my sister to even be counting the tip ($90.00) I left $30.00 my daughter left $40.00, Carol left $20.00, and my other sister had a $20.00 and wanted to leave $10.00 but my other sister told her she owed her $10.00 for something or another so she took the $20.00 and never put the $10.00 change back. Thus she took $10.00 of the tip. To make matters worse she said she left $30.00 which I know is not true.

Confronting her would be a huge mistake, some things are better left alone. My way of dealing with this is simply not giving her the opportunity to mess with my tip and I will pay separately from this point on. And I will also never invite her back to eat with me where my son or my daughter works.

If this is the worse thing my sister does to me or my family I will consider myself lucky. After ruminating (Jane10 you were right) about this I think she looks back and feels my family was given more by my parents than hers. In the end I really don't want to make this a breaking point for our relationship. So yes I have reconciled it, thank you all for your help.

Every family has their own strange dynamics this one might be ours

The one time we were in america was when we had a weekend with friends in new york and after a meal were chased down the road by the waiter demanding a bigger tip.
Service and food had been indifferent and normally we wouldnt have tipped at all so what we did leave was more than enough. The waiter had the nerve to stand there and argue with us in the street so i suggested he give it back if he didnt want it. He didnt. It was my 50 th birthday, one to remember.

Gigi if you plan to put tips on your card you might want to check that staff get the whole amount because here in the uk many restaurants keep some of it back and the staff lose out.