Alice, Do I Really Need to Replace a Wine Glass Broken While I Was Housesitting? -- Ask Alice: Advice For Life at Home

Dear Alice, 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 a...