It's not 'scummy'. It happens with probably all brands. They all have different levels of sponsorship. I know someone who was on Legacy's "Street Team". That is Legacy's low level sponsorship. One thing about tiered sponsorships is what I call 'control'. Most times, the lower level is not required to throw ONLY that brand's discs. My friend only had to have (I think) 50% Legacy discs. So an 'elite' or 'fully sponsored' person would be expected to ONLY use that brand's discs. Then as the sponsorship level gets lower, the requirements become less strict.
As for the player's wearing the brand's clothes....that might be strictly by the player's choice - kind of like bragging that "I'm a member of this team".