To look whether he wears a wedding ring - that's a good idea. But some guys have just a girlfriend or don't wear the ring. So, this indication is not absolutely clear. And I don't want to invite them all.
Maybe I should go down to where they're working and just talk a little bit. Maybe to ask some stupid question. How long the works will need. How the paths will be plastered. Which plants will be there. Such things.
I suppose his name is Sebastian. Sounds good.
@ Kev
why do you ask? it's Germany.