"HIGH RATED PLAYERS ABORT ALL THE TIME"
Most likely they want to play someone their level. and there are other few reasons why this happens, for example they wanna practice some opening so they wanna get the white pices.
"some players that are behind just let the time run out"
Many reasons can explain this, just wait the time and you will win. This had happended to me even in real life tournaments, the other player goes to wonder arround to see other boards, have some coffee, go to the restroom... one day an IM did this to me, came back he had 5 minutes in his time and I had some 50, and he still beat me.
You want to know what is unfair? that you are obligated to keep writing down the moves in a paper and your oponent not becouse he haves less than 5 minutes on the clock.
"many times a win gaves you no increase in score"
The points depend on the score the person you played with. So if you are 1200 and win agaings a 700 you have no prove to be better than a 1200. In the other hand if you are 1200 and draw a 1400 you will recive some 3 or 5 points for that, and the 1400 lose some.
I AM GETTING ALL THESE WARNINGS - WHY ? THIS HAS BEEN GOING ON SINCE JOINING ! HIGH RATED PLAYERS ABORT ALL THE TIME . some players that are behind just let the time run out ! many times a win gaves you no increase in score . IS THERE A CLUB DEMAND WHAT EVER THE RATEINGS YOU MUST PLAY ? come on get real , a 700 player must play a 1200 player .