Let's make a comparison:
Let's say a day's worth of yard work is worth $100. Ten home owners in a neighborhood need yard work done. They get ten unemployed people to each do the work on their homes. These people really need the money. At the end of the day, the person who does the best job gets the $100, and the rest get nothing. Ten houses worth of yard work has been done, but only one day's worth of pay is given out.
Yeah, you can get away with it, but it's because you're taking advantage of people. Just because you can ask for it and just because you'll find people to do it doesn't make it right.