This might look like a bog-standard misspelled sign, hastily put up with no real regard to spelling conventions. And yes, it certainly is; only there were FOUR of these signs in the park near my house, with wet written ‘weet’ on each one.
Such dogged devotion to the (mis)spelling is worthy of any in-house stylebook. And everyone knows that if you say something enough, other people start to believe you. I have to admit I actually checked to see whether weet was an actual word or type of paint. According to Google ‘weet’ is Dutch for ‘know’, which brings it all into a rather pleasing full circle.