As long as you got the service you paid for, I don't see any issue.

I did get very annoyed once on a longhaul flight when crews friends were upgraded to CW. I had no issues with that in itself.

The crew then told me they had run out of my meal choices (both starters and mains), and I didn't fancy anything else on the menu, so went without food.

30 minutes later, I see those dishes that they had "run out of" being served to their (unofficially) upgraded friends seated next to me .

If they want to give friends a better service than their friends paid for, I don't have a problem - unless it means service is taken away from paying customers. And even if you are going to screw-over the paying customers to keep your friends happy, at least try and do it discreetly, not right in front of the customer.