Multiuser issues with objects/scripts

Let's say I have coded a Simon game or a tic tac toe game, what's to stop different folks from clicking along with the original initiator of the game? Or another example, a vendor that cycles through clothing it sells. What's to stop someone standing next to me from switching the clothes out as Im trying to buy something? Is there a way to mark an object as "in use" and not have it react to interaction from other folks for a certain period of time?

Basically you have the players "sign up" to the game or vender either by being the first to touch it or to click a "sign on" button or sitting at a table (all kinds of ways). THEN when a touch_start event is triggered, you check the ID of the av that touched your object with a list of the names of the people that have signed up and if they are not on the list say something nasty to them

I've used "XXX is trying to interefere with the game!" before (but only do it once per name in a time period, some tards like to click it over and over and over to grief)

Most vendors lock to the first person that touches them until either a sale is made or a timeout ocurs.