Inspectors aren't the only people that you need to consider; referees have G20 to enforce. As an inspector I would tell you that those corners are probably OK; I'd pass your robot but warn you about the refs & G20. If they deem that amount of the opposite color unacceptable you're going to have an unpleasant match; G20 would be really harsh.
I have seen reversible bumpers that do not have
any of the opposite color showing; it is possible. Putting a bit of tape on really isn't a good solution; this isn't damage that needs to be repaired.
You should be OK, but remember -
inspectors are all nice and are always your friend.
It's those
referees that are evil, nasty, and just downright mean.
