Defacing your own election sign?

Let’s just say this is purely hypothetical to avoid any accusations etc…

Next door neighbour has a ridiculously large election sign on their front lawn…. I’m on a very busy road so anyone driving by will see it whether you want to or not…

So, overnight this sign was defaced with the words “climate killer” so I decided to check my cameras…

So…. my cameras picked up movement at 1:13am which just so happens to cover a section of my neighbours lawn. The thing is, the man that defaced the sign comes out of my neighbours garage and looks suspiciously like my neighbour…. And then returns to the garage and closes it..

Should I alert my neighbour that there’s a young hoodlum residing in his garage that looks suspiciously like him and comes out at night to deface signs?