Even using /s and having a sTaGgErEd fOrMaTiOn oF CaPiTaL aNd lOwEr cAsE lEtTeRs and even straight up saying "This is sarcasm. This is a joke. It is insincere.", people will still stupidly fall for it. I'm 100% serious about this. There is no level of precaution you can take that will be sufficient to overcome the infinite stupidity of humanity.

I once ran a D&D campaign for some college students which included a trapped treasure chest surrounded by the bones of other fallen adventurers with signs all around it in every possible language that straight up say the chest is trapped, and they still went to open it anyways, and of course, immediately died.

I honestly don't believe it's possible to have enough safeguards against human stupidity.