But is the SI system ambiguous? I almost never have to think about prefix v unit, it is always quite clear. Of course, strange combinations can occur (MNm - Meganewtonmeter as an example perhaps), but even those are unambiguous on second thought.
Collisions seem to be most prevalent in "IT" units or for improper SI usage. But maybe the latter is really the reason for the former in this case: if people separated SI and other units properly for IT units, it seems to be it would also be perfectly fine (but like me, a lot of people seem to have no idea of the correct definitions).
If you are strictly sticking to the SI system of units, you should be fine. However, some of us work in industries and countries (You know where) that don't fully embrace SI, and mixing other systems with SI is common.
Collisions seem to be most prevalent in "IT" units or for improper SI usage. But maybe the latter is really the reason for the former in this case: if people separated SI and other units properly for IT units, it seems to be it would also be perfectly fine (but like me, a lot of people seem to have no idea of the correct definitions).