[Grammar] use of defining/non defining relative clause after phrase 'the black van '

[adrenalinman]

The black van in which the gang members escaped had no license plate.
This is a sentence I got from a test book.Doesn't it have to be non defining as we use 'black' in front of the word 'van'?
The black van, in which the gang members escaped, had no license plate.

1-) I think we can make it both defining and non defining but it depends on the situation.Surely they both have different meanings and contexts.We do not have to use a non defining relative clause just because of the word 'black', do we?
2-) Could you please explain in which context we must use 'The black van in which the gang members escaped had no license plate'?
3-) Could you please explain in which context we must use 'The black van,in which the gang members escaped, had no license plate'?

 

[bhaisahab]

It's a very unnatural sentence. No native speaker would say it that way. Therefore, there is no context in which one might choose one over the other.