Hey, we had one of the exact same problems with our ball poker (a PVC pole that is winched up inside of a slightly larger piece of square aluminum). We found while testing at the Cheezy Poof's field (thanks again, guys!) that if we hit the ball near the edge, the ball wouldn't fall down but would rather push our pole against the overpass rail while it was coming down. Doesn't sound so bad, except that it became impossible for our winch to retract the pole, causing the fuse in the spike to blow, and leaving us with a robot trapped in the tiny square of the overpass. Eek! We replaced the pole with something that won't bend (huzzah for spare axles that fit inside pipe!) and added a rangefinder pointed straight up so it will be easier for us to know when we're under the ball to hopefully mitigate the problem.
Depending on how fast the scissor lift is, retracting as soon as it is up may not be enough. Our poker did that (after a small delay to reduce wear on the winch transmission) and still got pinned, though it's certainly a good idea to come back down as fast as possible in any case. Hitting the ball closer to the center would probably be the most effective strategy, and the drivers can use the tape on the finish lines to help them line up, something we couldn't do on the practice field.
For being concerned about the ball landing on your arms, could you just turn the robot before you poke or if the ball starts to fall? It would take more time, but should help prevent that problem if the arms are safely under / on the other side of the overpass.
And high five for your fellow ball-poking and arms-for-herding robot! Hurdling is SO overrated!
