Unless it were a ROA in which case it might bring your judgement into question, but aside from that I can't think of any negatives to being whitelisted by an agency.

It is funny however that I have the dubious honor of having more white listings than I have reviews. One vs zero. and ironically enough my white list is from a provider that I know but have never seen professionally. Go figure.

Real friendships in the hobby.

I have many real friendships in the hobby, with both hobbyists and providers alike.

of agencies whitelisting people who have seen the agencies own providers.

Who else would they whitelist if not their own customers?