This use to be true, but today it is false. Most placement of machines is done for marketing purposes. Majority of slot machines today are leased to the casino under contracts from the manufactures. Manufactures will sometimes have stipulations on where the games are to be placed. Newer games are often times featured front and center as part of this agreement. When new games arrive, the casino has to make room for them by moving or removing machines from the area. Casino floors are always changing so make sure to always walk the floor.