agreed, pleaaaaaaassssse go to standby when changing squawk!
Even you military and PPL types. We get a load of incorrect corellations between flight plan and radar data due C172 pilot stopping mid twist to answer the R/T. GBAEW converts as BAW225 and the systems try to track the flight. Controllers know which is their aircraft but the systems aren't so clever (maybe perveptive is a better word here).
Can be a serious problem close to the boundary.