...”the official cylinder may be losing mass....”
...spoken like a true scientist. Or, it may not be. I suspect there is a program (which will be very expensive) which will open the official kilo, and determine if it really is losing mass...or not. After all, our methods of weighing things has improved since the official kilo was put into the domes. Most likely it will have a different mass than the last time. Who will know if the mass changed, or the scales changed?
Being an ex-calibration technician, PMEL, I used to keep up with such esoterica.
The NIST (formerly NBS) was working on an experiment a few years back that would do away with the physical standard for the kilogram.
They were meticulously winding a giant coil in an effort to use magnetic force applied to a solenoid type plunger to determine if that could be used as an ‘electronic force’ standard.....since I have not heard anything since, they must have abandoned it....
“Who will know if the mass changed, or the scales changed?”
Easy, you can tell if the scale has changed by using a 1 kilogram weight standard, no wait...