(Sorry I'm late to the thread)
Yep, I do this all the time. But I don't inform the player that there is no chance for failure...I ask for the roll same as always, and then tell them the result they get. If failure was never really an option, I'll tailor the description of the result to match the quality of the roll, even if failure was never really an option.
I think that suspense and anticipation are important elements of the game, and I don't want to ignore or waive them just because of numbers on a character sheet.