Anyone ever used this Demoman tactic on Stage 3?

I've tried this a few times and have net a few kills, but last night was the time where it got me a ton of kills and caused spies to bypass my teams' sentries to come backstab me. So, the game starts (8v8) and I start lobbing pipe bombs over the roof (the little alcove with two small medkits, have to go upstairs). I got a ton of kills like this, and eventually spies were coming over to backstab me several times. I got 21 kills in one life doing this once.

Not on our servers o.O

I just finished watching a video and think this needs a bit of clarification...

If anyone's seen where Demomen can stickyjump up to and see the BLU spawn clearly, that's where I was, only on the ground. I was just aiming upward and launching the pipe bombs. My team had them in lockdown over there and so they were all properly placed to take a few crits.

(@ Verden - If you mean that I wasn't doing it on your servers, I don't play the PC version. If you meant you've never tried/seen people try it on your servers, then ignore the parentheses.)