I am well aware of the legality of using a marine radio for shore to shore comms. My ham 2M radio can receive everything from the aviation freqs all the way up through the marine freqs & I have some of them programmed to scan sometimes.
Quite surprised to hear marine channels used far from any water & obviously non water related use.
Not saying it is OK however a handheld radio on low power is not having a range of more than a few miles at best.
For CG parking & not losing each other in a big box store the best to use is a cheap FSR. If it gets destroyed by dropping it or getting it soaked, no big deal.