The most effective way of "cheating without cheating" is just using something like Sauce for Zwift or a head unit that displays your rolling 20min power, so you can effectively "sandbag" and keep your power under the threshold for the next category. This is arguably not cheating at all, just smart racing, but it is not a great racing experience when you're in the top third or so of a category and you race someone who very clearly is far superior and only staying in your cat to rack up podiums.
To be fair, though, 1) this makes a lot of sense for team racing series, and 2) it's a really crappy experience to be at the bottom of a category and get dropped within 2 minutes of the start of every race.
I'm 100% convinced the vast majority of people either outright cheating or gaming the system are Cat C riders trying to avoid getting upleveled to B.
For heavier riders this is almost the only way to enjoy racing on Zwift. Even with a high FTP, I will never compete in A. So I jump in B races, use them as sweet spot training and get some sprint in at the end.
To be fair, though, 1) this makes a lot of sense for team racing series, and 2) it's a really crappy experience to be at the bottom of a category and get dropped within 2 minutes of the start of every race.
I'm 100% convinced the vast majority of people either outright cheating or gaming the system are Cat C riders trying to avoid getting upleveled to B.