DH and I had a Big White Wedding at a very swanky mansion. We'd booked it and in the contract, it said we'd pay for beverages (sodapop as well as alcohol) plus a 20% tip. It was mandatory - no option. Sounded good as we didn't want them asking for tips from our guests.
We were talking to friends of friends several months before our wedding and we told them where we were getting married. They told us that they had attended a wedding there and there had been a gigantic tip jar on the bar! I was soooooo glad that they warned us that apparently other patrons paid the mandatory 20% tip AND the service staff had still had the audacity to put an additional tip jar up on the bar!
I immediately called the mansion and had them put in writing that I did not want any additional tip jars placed anywhere. I asked the wedding party to keep an eye out for tip jars as well, in case the mansion didn't do as instructed.
I tried to look, but we had other priorities during the wedding, of course, so I am not certain they did not put out another tip jar. However, none of us remember seeing one.
They did ignore a few other things in the contract though. We specified that no wine over $10/glass would be served to guests. After we paid the final bill, we saw that they had served some $25 glasses of wine. Things like that.