Can you explain how the money flows?

If I walk into a UPS store and pay the store $10 to have a document notarized, I'm pretty sure that's just regular income to the store.  If, instead, I pay the individual at the desk (who is also a notary) $10 personally for notary services, then that particular individual may fall under the SE exception as a fee-based official (but they need to keep detailed records segregating notary income from other income).  Unless your client with "a bunch of UPS stores" is the one doing the notarizing, I think it's just going to be trade or business income.

Just my $0.02 worth.