It is part of the responsibility when you are a supervisor/manager at any business. It is not unique to UPS. I do not get a whole lot of calls once I leave for the day because my people are trained to handle things when I have left for the day. The same can be said for them, once they leave for the day they rarely get a call from me.
To address the retirement at 55. The last drivers that have retired in this area (25+ years) are working jobs that pay them $10-$15 an hour they are working 40+ hours a week at that job and paying $400 or more a month for insurance from the teamsters. Sounds like they got it made. A couple of them were old enough to start collecting SS...they were well pass 55 if you get my meaning.
If we were really that smart, maybe we would all have worked some where else early on.