X.O.
Yes, I did it for my friend and her husband about 8 years ago. They wanted to visit Chicago, but I was going home to the Twin Cities, so they picked up a key from my parents in MN and came to IL. When I returned a few days later my friend had a vase of flowers and had prepared & frozen a lasagna for me, but otherwise left no trace.
It totally depends on the specific friends, but her, I would do it again and again.