This past weekend I was house sitting for some very well-off friends. I got the go ahead from them to have people over for dinner and one of my friends broke one of their wine glasses. He offered to pay for it, but I also know he is about to move, doesn't have a ton of spare cash and the replacement glasses cost kind of a lot ( and you have to buy a set of two). Do I go ahead and accept his offer? Do I replace the glass myself? Do I tell them and hope that they'll say, "don't worry about it, we're RICH!"? I know he feels terrible, I feel terrible that he feels terrible, but I also know these people don't need two more fancy wine glasses. Ugh!
Sorry to Wine
We've discussed a more straightforward version of this conundrum on Apartment Therapy before and the general consensus is to ask the host and if/when they politely decline your offer, send some sort of token as a gesture of atonement. I'm in general agreement with the group of commenters on the original post, but things get a little more complicated with the added layers of who should do the apologizing and buying, you or your guest. So let's break it out.
I know it's hard not to get into the wallets of people who are seemingly well off and conclude that they don't need a new wine glass, but I would advise against just assuming. You should tell them, offer to replace it in earnest with the expectation that they'll say yes. If they do, you should replace the glass, not your guest. You assumed a certain amount of risk entertaining in someone else's home, and when hosting one goes into it knowing accidents happen.
Now, there's a 99.9% chance the homeowner will turn down your offer to replace the glass, perhaps send them a nice bottle of wine as a gift? It's a nod to the broken item, and everyone can use more wine. There's also a big chance that even if you tell your friend who did the glass breaking not to worry about it, he will insist on helping out too (this is just one big push and pull of guilt and manners and perceived obligation, isn't it?) and if he insists on it, split the cost of the wine with him.
Long story short; honesty is the best policy, send your rich friends a token of some kind, let your clumsy friend know that it's no big deal and next time you host a dinner while house sitting, use the cheap stuff.
Cheers to you!