I come from a very competitive background (Varsity/minor league baseball growing up, competitive cards, and even the competitive workplace)... so the very thought of giving my opponent a break simply does not register to me.
IMO, if it's a "rated" match, it qualifies as a competitive environment. There is nothing I would ever do to reduce my winning percentage (excluding ethics/moral issues, such as declining to abuse some programming bug, etc).
If someone is playing anonymously for a non-rated game, then sure, I'll skip my turn, heck I'd even resign myself and in my head know that I won. But if it's a rated game, even though there's really no money involved... it's rated, it's competitive.
Someone says they'll resign on their turn? Sure go for it, but first you are going to sit through my turn, because I'm going to quad-province after my 2 min combo. If you don't like it, go take a bio break and resign when you get back, but I'm not giving away any edge. Life is tough. Nut-up Sally.