That's not nearly as talented as molotoving yourself.
Which I've done, on numerous occasions.

If a tank was charging you, thats fine.
Otherwise...
If I was playing as hunter, and someone did that, however I would leap at the oppertunity. Woo extra fire damage.
Speaking of MP fails. Halo reach on spire. The reload button is the same as the button to hijack a veichle. I never really learned my lesson, and got splattered by many banshees. I hijacked alot too, but still.
Also jumping off the spire, thinking you have a jetpack.