I generally (if conditions allow) switch OFF the seat belt sign at 5000agl...after all, we pilots get thirsty, and our gals make excellect coffee/tea.
You inadvertently raise an interesting point Bob, which is that crew release and belts may be one and the same or two different steps. Our crew are up and about at 3000agl, wx allowing, and if on top form can have our drinks with us before the sponsors are released at FL100.
Wally.