A few years ago, I was sitting next to an ongoing game. It was a championship game of a mini, and they had chosen to play Puma Prowls.
Looking at the game, they were in turn three and the Pumas were swarming and the T-70's were in a line, on the road, and not very far on board. So I asked them if they knew that in 1943 T-70's were radio equipped. They didn't.
Well, I thought it was information they needed to know. Unfortunately, they felt they had wasted valuable time. And while they were thankful for the information, and the knowledge about the scenario, one of them had to catch a plane so there was no opportunity to restart.
I thought they should play the scenario properly, but afterwards I had second thoughts, it was thier game, not mine. I should have let them play it out, and since then I have kept my mouth shut.