Syncthing can’t “delete everything on the laptop”, which (as you point out) are the words the OP typed. Because the first paragraph was about sync directories, I interpreted the question (perhaps incorrectly) as “delete everything on the laptop in the syncthing directories I just told you about”. After all, the context of this forum is Syncthing (not general laptop data destruction) and the title implied the OP knew that the sync node trust relationship would be eventually deleted, but the OP wondered if sync thing files could be deleted first surreptitiously by running syncthing as a service the bad guy didn’t know was operating. ~That~ idea is no different than the position reporting OS services that let you find your lost phone.
No, syncthing can’t delete everything on the laptop (docs, data, apps, the OS itself, etc). Yes, syncthing can delete the syncthing directory files. Guess we’d have to hear from the OP to know which question they meant.
Sorry to offend you. I referenced Audrius (as I try to always reference who I’m replying to) to keep track of which person I respond to in a thread. When I refer to “should have said” in my second reply (note my first post was a question to understand), I wrote as a technical engineer in a computer support forum. It would have been better if I just pointed out the technical reality and was more careful implying what someone else should or should not do. In context, these aren’t intended to be moral or professional debates - it’s a tech support forum.
Lastly, hacking around with tools and trying things out can yield goodness. Everything needn’t be a 100% secure production server. Original and wonderful ideas come from experimenters, hackers, and early adopters, stretching the envelope of what its possible. Since the late 1970s, this is how a lot has been learned in the computer software world. Jacob’s reply captured the thought - for project management reasons, there ARE reasons to deter risky ideas. But I think it’s okay that some people keep trying new things. Disclosure - my day job is a cyber resiliency expert on military weapon systems. Believe me, you MUST push boundaries in that context and try all sorts of “non-documented features” to stay ahead of adversaries which are doing so.