They make belly pan protectors for this very reason & to protect the coolant overflow bottle from puncture. I've had one on my bike since day one.
Sweet, I didn't even know these existed. I need one!
PS: I'll never understand why manufacturers of high-end products try to save money on the smallest things. The whole Gold Wing family is as high end as it gets, from a tech point of view. On one hand they spend major coin on putting abso-f-ing-lutely expensive and boneheaded contraptions on these bikes, like the tank lock. But when I drop $29,000 on a new Wing I've got to go on Ebay, find an aftermarket part, and start fiddling with stuff? I as a customer have to eliminate a well-known weak point on my bike that could render it completely unusable, because Honda can't be arsed to put that part in at the factory, which would cost them probably less than 20 bucks.