The case when you lost connection to steam...

...works pretty well. An in-game dialog pops out and informed me.

But hell no why does this always happen when every kill gave 100 points extra and your team is close to see a happy nice smiling pitgirl? :evil:

It's nice that it informs you that you've lost connection to Steam, what's not nice about this is that you have to click through the warning to continue playing. You'll have to find a way to make it noticeable, but keep it from dominating the screen.

Perhaps have some unobtrusive text show up when it happens, but then also add an indicator to the skill picking menu, the scoreboard and the death screen. It could simply have the warning at the top of any of these screens. en.