It seems to be a real definition, see definition 6 under etymology 2:

> (transitive, law, especially New Zealand)[1] To subject [someone] to a trespass notice, formally notifying them that they are prohibited from entry to a property, such that any current or future presence there will constitute trespass, (especially) criminal trespass

https://en.wiktionary.org/wiki/trespass#English

Ah, I thought that could be the case but didn't see it listed in Merrium-Webster [0]. Seems like it is legal jargon, so might be better to use plain language here.

0: https://www.merriam-webster.com/dictionary/trespass