The thermostat is paired with the boiler, the signals bundle the unique ID’s of each so this won’t happen. Otherwise there would be a risk the original thermostat would do the same.
This did come up when I was researching this but it’s incredibly dangerous as you’ll be spewing all over the spectrum due to harmonics, I considered it too much of a hack for my liking
Posts are linked with accounts and blasting old posts out as if they are new is not practical in a federated network, and since Mastodon doesn’t support backfilling (and likely never will) it’s just not going to happen. This isn’t even getting in to the logistics of redirecting replies and likes/boosts. The GitHub issue for it has been open since 2019.