You got a good point, if that's not a part of your contract then dismissal should not be the first option, there's should be a warning first before dismissing an employee as you mentioned it can easily be abused by any higher authority in that company since they can quickly decide to punished you with dismissal if they wish using that kind of reasoning, though it's tough decision to make since employers or any head of the company have that authorization if that's part of the contract then there's nothing to talk they can simply implement the dismissal.
But check the clause of the contract you sign, maybe there is something written there about terminating the contract and the employee at any time the company sees some valid reasons in doing so.
While there is a certain abuse to it but the employee doesn't have any power to alter the decision once it is final based on the basis that the company has seen to dismiss the employee by doing such acts.