My suggestion: encase it in a clear plastic part of the boattail, but make this part on the bottom so the bright sky reflections don't "obscure" the plate. The
law says you can have something covering the plate as long as it's still easily readable.
As long as you don't have blurry plastic or bright reflections over the plate you should be fine. Of course this is all subjective, too, so if the cop feels like it he/she could presumably write you up. (And you easily get it dismissed in traffic court)
I've gotten pulled over twice for license plate violations. The cop asks me a couple questions etc, I act innocent and be polite, they go look up my clean driving record and let me go (and then I go home and fix the plate). If your record is clean don't worry about it.