Paws, I urge folks new to the use of marine VHF radios to get decent training, and to practice their use on the water. If you have a buddy who can work another VHF on one of those TN lakes that would be a good locus for honing your skills. As for the certification requirement, I would wager the vast majority of US paddlers on Canadian waters who carry a VHF radio do not meet the requirement. I suspect that is true of US power boaters as well. Does not make it right. Does not make it legal. I have heard that the training course needed to get certification is useful, but not sufficient. YMMV.
As for concern about being cited for lacking the certification, someone more familiar with those data will have to chime in. In remote areas, my experience is there is no enforcement, and local choice of channels does not always conform to the official listing. To wit, in the Charlottes, channel 06 seemed to be a hailing channel and a communication channel. Sixteen should be monitored, but the groups I polled, three summers there, rarely turned their radios on, primarily to conserve batteries for use in a true emergency.
Twice, over the course of many years, I used my VHF from the beach to help paddlers. One of those times, to initiate a sortie to locate a pair of overdue paddlers. The limited range boat to boat makes that impractical unless you prearrange contact times and work off the beach instead. However, reaching out to a CCG repeater atop a nearby high point is often a very reliable way to get help.