What I could see being an issue, is that all the other outlets are now dependant on the UPS being there for them to have power. Obviously I'm more familiar with the Canuck codes then the NEC, but if this is an office in a home, there would be requirements for receptacle placement.(any wall space is within 6' of an outlet for example). If you unwire those other outlets so that they are dependant on the UPS being there, I would say that it doesn't meet the code requirement any longer. A UPS is not a permanent fixture, and if you moved and took it with you, the new owners would have no working outlets in that area.If you find the first receptacle in the chain feeding a office area. Remove it and then add a outlet and inlet would that be against code.
I have a office area for me and the wife and its covered in cables due to the ups unit if i could move the ups to the first receptacle then feed the rest of the receptacles off the ups that would tidy up the mess and it doesn't seem against code as all the receptacles are 15 amp.