Beware of R16 your robot design may be too big.

[StevenB]

On a side note, I do not think it will be that hard to referee this one. If you are designed to lift a ball, they will ask you to demonstrate it at inspection and they can measure then.

Until you do it on the field though, there isn't any penalty. They can't fail your inspection because of it, any more than they would be able to fail you for being able to violently ram another robot. The most they could do is make a list of robots to watch.
It's possible that FIRST would make a rule saying that your robot has to be mechanically incapable of exceeding the size limit, but I find that unlikely.
I can see them pulling out tape measures, but as I mentioned above, that isn't equivalent to making sure to robot fits in a cylinder.