I think it is fine for the parent to walk with the kid selling door to door.(recommended for safety)
At the office it should be low key, make a no pressure announcement. Many people actually love the cookies. It is like crack to some. They sell themselves to a certain degree.
If you like the cookies then buy them or maybe buy one box to support the kid and donate them somewhere.
A real estate lady in our neighborhood buys tons of "thanks a lots" type cookies to give as a thank you along with a thank you card for little favors.
My daughter, no pics but you can see one in the dog thread, has really grown in her ability to sell and/or present her spiel to people as she has gone door to door for the last couple years.(and she went with her brother the year before)
Buying the camp cards, the popcorn, the cookies, is something to support the kids going to camp, etc. Plus it is a boost for self-esteem, etc. I'm much more inclined to buy from kids now that I've seen mine go through the process.