Is this a joke, or are you so out of touch that you don't think a labourer could have a desire to ever travel?

As a purely leisure traveler, I can't see why anybody would put themselves through the US border system as the start of their holiday. Talk about starting on a downer.

There's currently a huge demand of plumbers in the US, because the president said he wants to drain a whole swamp or something.

and bricklayers

Why would a software engineer want to visit the US?

For example to attend a conference. Things like a "World Plumbing Conference" exist, though I'm not sure if it was ever held in the US.

I was once going through security in Romania when a plumber was in the queue. He'd brought his full tool kit with him, which provided much hilarity for the security personnel as it was obviously full of things you're not allowed on aircraft.

(Not everyone is a seasoned flyer who knows the rules!)

To see which way water rotates when it goes down the drains, of course.

Are you being serious?

Have you seen their toilets? Plumbing nightmare

Perhaps his Princess was in another castle...