From RUSA's Rules for Riders at http://www.rusa.org/brvreg.html :

Article 6
Each rider must be self sufficient. No personal follow cars or support of any kind are permitted on the course. Personal support is only allowed at checkpoints. Any violation of this requirement will result in immediate disqualification.

(emphasis is as shown on the RUSA website, btw)

So you're right Mimi, along the route itself you can't accept "personal support" from anyone except someone else on the brevet itself (which means that person isn't "personal support").

But at the checkpoints it's OK.