One of my team mates ran across this situation in a match a little while back and shortly after that match I saw Efren Reyes play exactly this safe in a televised match of 9 ball on ESPN...(of course Efren played it to perfection). It is a shot worth learning if you don't already know it. It works great in 8 ball when you and your opponent only have 1 ball each and he leaves you hooked on the 8 ball while his ball is in and easy place like the middle of the table.
Think of all the times and places you would have won if you had played this safe....