The "20 reservation per year" is simply a metric that Disney uses to help identify "commercial" use. There are situations where someone makes more than 20 reservations for other people, but is not using the membership for commercial purposes. And, counter to that, they could change the metric or use some other method to identify people who are making commercial use of the deed. You should plan to pay within the bounds of the legal contract. Don't take a "we won't get caught" approach.
ESPECIALLY since Disney has been big on using technology to close loopholes. Software will tell them how each name on a reservation is connected to the owner of the contract (seriously - its used by eCommerce companies to spot fraud - if you are sending a big TV to a person and address that isn't yours, they can (and often do) run it to make sure you know the person you are sending it to) - and 'commercial' isn't defined. So its not too difficult for Disney to say "if you don't know people on the majority of your reservations (they aren't friends or neighbors or relatives), we flag you as commercial.
Loopholes closed or policies enforced that weren't previously for reference - refillable mugs, transferable tickets, gated pools, resort parking, Fastpass return times.......