Bad advice. Merely because you might have gotten away with it doesn't make it good advice.
Your issue with the deadbeat is a civil matter. Repossessing a
sign can be a criminal matter. When the local gendarmes arrive they don't care a pinch of ossified wombat snot who owes who what, that being a civil matter. They would, however, be interested in what gives every appearance of a case of grand theft
sign. With you being the thief and the deadbeat being the victim.
This could even go so far as you successfully retrieving the
sign and then the deadbeat filling criminal charges against you. And making them stick. This level of functional a$$hole is seldom encountered but they do exist nonetheless.