First of all, there is absoltuly no way for you to know if there were any empty seats on this flight without being able to see inside Unitedīs internal system. Just because they were selling seats on the flight, it is quite possible was occupied by the time she arrived. Secondly, Iīm willing to bet that the agent had no idea the flight wasnīt going to depart ontime. Agents very rarely know about delays to to servicing or bag loading, unless they are advised to delay boarding. Lastly, United closes the doors ten minutes before departure. Just because some agents will try very hard to load standbys up until the last minute, we all know (or should know) that this is their helping us, not what the rules dictate. If she had alread been on the standby list for that flight she might have had a chance, but in this case there are way to many variables to be able to say that agent was rude/lazy/dumb.