I would agree with Alan. If I were doing these kinds of games I would want to know that my opponent is aware of how it works and what's required in terms of a time commitment. There have been countless posts on the BK board of people - including experienced BKers - expressing "What does .. mean?" and "Oh, I didn't know that" with regard to the clocks. With newcomers to the site they don't even know to ask the questions.

There's one player (in Linetris) who delights in winning games against newcomers who don't know that they must stick to the game like glue or lose it. What a great welcome he gives them to the site; their first experience here is to get shafted!

For me it wouldn't be fun or acceptable for anyone to lose to me because of the time. Each such win would be a cause for regret if I could have helped the opponent avoid it. Clear notice in the game invitation would be one part of that. With a new opponent I'd ask them on the first move what they understand about the clock and time constraints. I'd do it then so that I could delete the game if it turns out that they didn't realise. In other words I'd make it my responsibility, not theirs, to avoid winning because of the clock.

That's not to say that you should, just that I would. Part of it is that I care about my opponents but another part is that I care about my games stats. A 66% winning ratio isn't of such value if it includes too many non-playing wins. Others don't care two hoots about their stats. ;-)