What regulation did they reference for this? I see nothing in CFR 91 that limits passengers during banner tow operations, nor in the Advisory Circular about information for banner tow operators.
Is this something that is specified when they issue the waiver? I still do not understand why a banner tow operation even needs a waiver. The only theory I've ever had but has not been confirmed is that a waiver is required because of 91.119 and since a pickup/drop is below the minimum safe altitude numbers, but a landing is not being performed, then a waiver is required.
Houston?