Great to see all these perspectives on the OP's question.

I do apologies in advance for jumping in, but I'd like to cheekily throw in a question of my own

Given you know that the people are not in the correct group, how would you handle people blocking the way into the jetway/document check when priority boarding is called? Will you barge in or wait?

Granted, this isn't a question that is valid in every airport (esp. those with priority lines), but rather those employing a pen like system (Kuala Lumpur and Jakarta in particular comes to mind)