RollerCoaster Tycoon Cheats

You can have more than one person with the same name by changing the capitalization of the name's letters.
Example: There can be four or more Chris Sawyers in your park if one is named Chris Sawyer and the others chris sawyer, CHRIS SAWYER, and cHrIs SaWyEr.

In some versions of the game you can buy signs and there is a hidden trick you can use with this.

Place one facing away from the entrance right infront of it.
then right click it and click the no entry sign on it and none of your guests can leave.

When a guest is about to walk into your park, pause the game. Make the price of the park exactly one dollar less than what the guest is carrying. They'll always come in, no matter what. If it's the exact amount they have, sometimes they don't come in.