Create functionality to specify a Master probe tip, such that it removes the ability to define reference sphere location with any another tip.
I imagine this would be relatively simple to do, and of incredibly high value to the end user.
Once tick box in Setup somewhere to 'Use Master Probe'
Once ticked Select a Probe & Tip combination which is the master probe.
Once enabled, when you click measure if the probe tip isn't the master probe then the option to select Sphere has moved (either manual or DCC) is disabled.
Likewise the No - Sphere has not moved option could be disabled for the master probe/tip.
The only 'complexity' I can think of would be if the user went to calibrate the Master probe with a user defined calibration order where the Master tip wasn't selected first.
Customer support service by UserEcho