I've got one of micro-USB cables from Motorola, it charges my 8220 just fine but no sync. I didn't need sync with extra cable, so I knew what I was getting - and price was very good (almost free).

Looking at cable that came with blackberry (charge/sync) and Motorola one (just sync) I can't tell the difference betwen them.

So, it might be that people get sold Moto or other non-BB vendor cables, intentionally or not.