Works nice IMHO, depending on:
1) the unit you're protecting is worth the effort (screening multiple units will be difficult because of point 4)
2) you're willing to sacrifice one of the best scoring units in the game
3) said unit is big enough to not get shot to bits etc.
4) the dicegods don't screw you over with DS/run moves (and they will:shok
So how big is your unit and what do you plan to screen?
PS: you can see my list a couple of posts down. I plan on using that tactic aswell, but I'm not very experienced...