Demo slots let players spin the reels for 10 to 20 times and determine how many winning combinations they can land. They can also help avoid financial losses and improve their game-playing skills. Free slots can also help novice players or players who aren't experienced practice winning strategies.

You may get in trouble if the casino has a policy against filming, but the most they can do is ask you to stop or kick you out. If you're only filming the slot machine itself and not other players, then you're very unlikely to get in trouble.