Not, in fact, a requirement at all unless the customer explicitly identifies (in the SoW or T&C) some time, event, or circumstance at which it becomes mandatory, in which case they would more properly be represented by classification of the CI in question. Usually, just an indication of what the customer wishes they could have, if they could get it for no impact to cost or schedule as compared to the threshold requirement.
Objective requirements are often included in a specification to fool End Users and other interested parties into thinking that their perspectives have been given due consideration, forming part of the smokescreen.