As all of us know here, airline rules can be very complex. It is nearly impossible for a single agent to keep all of these in mind. Yes, that is what the airlines expect the agents to do.
A good agent will look up the rules, once you question or point out the correct rule. However, as we know, that is the exception rather than the rule.
Let's keep sharing things here on FT. Then, we understand what the correct rules are. However, let's not be TOO hard agents on the agents during this very stressful holiday season!