AKA It makes no difference which group of people it is about, it still sounds very threatening.
As you rightly say. There are people who find this country is not for them, the streets are not lined with gold, and they may appreciate help to be repatriated.
But driving that van around the town is not going to make anyone feel comfortable or safe. That is supposing they can read English well enough to understand it.
How would you know you are not going to be thrown into prison and beaten. It possible happens a lot in some of the countries this group of people come from. It's another reason why they feel the need to leave.
I also suspect that most of this group in this country are employed and get paid cash in hand. You could still be under the minimum wage and possibly earn more in the black economy than you could in your home country.
This is a difficult issue, the immigration situation in the UK does need controlling, we are a very small island, but this sort of tactic will do no good at all.
But everyone should think about this!
What lengths would you go to to make better provision for your family?
You are living in great poverty in your home country with no chance of improving this as your country's economy is dead!