The situation is a no-win situation for any involved. I've been on both ends of the outcome, more frequent the losing end. Here's my 1 cent worth:
With playoffs 2 weeks away, you want to make sure your starting unit clicks at all times. So getting them minutes together is crucial. Personally, I would think the starting 11 should get a 3-4 goal lead then play possession for the remainder of their pre-determined time is the best practice they could get! Or you make them play so many consecutive passes before shooting, up the number each shot. Or can only score on headers, or crosses, etc... As a coach you know there is something your team needs to work on, this is as good a time as any to work on that aspect.
It's equally important to get your reserves in the game as they can become a key player at any moment (injuries, cards, attitude, effort, etc...). Not to mention those reserves have worked just as hard as the starters and deserve the playing time. To put a reserve in and tell them they can't score isn't fair to all the training they've put in. I do think you let them score to a certain number, then you tell them no more and play possession.
I do like the idea of taking players off, however that can be just as disheartening for the other team when they can't win a ball from the other team that is playing 2-4 players down! Personally, I prefer mixing my lineup up and putting players in positions they aren't used to playing, make them grow as a player and perhaps respect another positions work.
Being on the losing end you hope your team will play the full 80 minutes with heart and play for pride. Being a non-traditional soccer school playing a tradition rich soccer school, your players can learn a lot from watching how the other team conducts itself. How are they passing, where are they positioned, where are they making runs from, how are they communicating, etc...
If the losing team isn't playing hard, then the other team is not gaining any valuable experience from the match and probably would've been better off staying at home doing an inter-squad scrimmage!
Like I said, this is a no win situation for all involved.