Resigning in a lost position is very polite and gracious. However, not resigning in a lost position is neutral. It's neither good nor bad. it's perfectly acceptable to play it out to the bitter end. Think of it this way - it means your opponent wants to learn from you the most efficient way of finishing off a game in a won position. They showing an interest in what you will play and trying to learn from you. Be flattered.
As for using up their time, it's their time! It's not like they can use up the time on your clock. Don't begrudge people the use of their own time in whatever way they see fit. By agreeing to play a 30 minute game against someone you have accepted that their play may use up up to 30 minutes. If they want to use 5 minutes on their first 45 moves, and then 25 minutes on their 46th move, that's their choice and not something you should criticise.
I have recently had a lot of players who disconnected after I captured a minor piece or just had a winning position. I'm wondering if it's starting to be a trend of some sort? I hope that all the unpleasant users sees this post and thinks twice next time they disconnect or let their time just run flat out.
Because what you actually are doing is wasting other peoples time, and a polite user would have enough respect for himself not to do that. But by all means, if you want your account restricted in the end, that is entirely up to you! I'm just stating a fact!... and another one; that all of us "ordinary" users actually want to play chess, not waste our time (money?) on douchebags who doesn't even bother to resign.
Please, hear me, and I hope you actually start being a sport, all of you. And if you are, I praise you! You are wonderful :D