Judgement.

It must be considered an informative clause for the employee, one in which he or she expresses a consent that is not strictly necessary if he or she wants to perform the services for which the employment contract itself is entered into in the first place. In that case, the employee may suffer the contractual effects of that decision (for instance, a fair dismissal if the employee is not willing to properly carry out the work that is specified within the scope of the contract). One must differentiate between those activities that although not frequent are within the object of the employment contract and other activities that are completely exceptional and usually out of the scope of the employment contract (for instance, employees whose images are shown in an advertising campaign). [Extracted from the article]