Because the Official Q&A is locked I am asking this question here to get a community response.
Is it allowed to place buckies on an opponents robot in autonomous? I know it is illegal to do as per SG8.a but rules like pinning are only applied in driver control, so would this rule be applied only in driver?
You cannot place any Buckyballs on any opposing robot during any part of the match.
The reason pinning isn’t counted during Driver Control is the following.
If you read , there is no such qualification.
OK, do you think there would be a difference between throwing the ball and placing it directly?
I am 100% sure that it is not legal in any form to intentionally place game objects onto an opposing robot. Throwing them randomly and having one hit a robot wouldn’t be an issue, though. If you really want a clarification, there’s an open Q&A at Worlds on… Wednesday I think. Maybe Thursday morning. You could always ask Karthik then.
Why are you asking, though? says
You can’t force DQ’s with this.
Throwing could probably be seen as accidental, and the chance of getting it in a moving robot is pretty low. Anyway, what good would it do, as I would believe from previous rulings and some G1 that you wouldn’t get the team DQed by that.
Also, how in the world would be able to accurately find the robot and place it every time. 
This is just my ‘opinion’ from interpreting the rules and Q&As and is not necessarily correct.
Theoretically, you could use a couple of Ultrasonics. Wait until they hit pre-set positions you can track, like in front of the goals or hitting the large balls off the barrier. Make the robot shoot to the specific position you want.
If that had been a legal strategy this year, I could see someone doing it. Hence the manual update.
One possible reason to do it in auton would be to make your opponent stash your buckyball for you. But even if that were legal, it seems so much harder than just stashing the bucky yourself.