It would depend on the relationship and how they would behave.

If it were my parents, I would do it if I felt it was necessary as they would honestly want to help.

However, I would not do it with my FIL as he would believe it is something that he can hold over us.

Personally, I don't think I would do it generally as I would feel that I was taking advantage. I will not behave like my sister (whole different story there).