Tailoring a field to your strengths or an opponent's weaknesses isnt cheating, it's OK. All sports have a way of creating a homefield advantage so this falls right in line with that.

They don't call it homefield advantage for nothing LOL!

According to legend, the grass was grown so high at Wrigley field that you could lose children in the infield. (Meant to slow down ground balls) Another trick is to flood the home plate area and the areas around the bases until they are mud-baths (Slows down those pesky runners) I tend to think this is clever home-field-advantage instead of outright cheating.