Is your brick a sand-faced brick (usually the bricks look weathered)? If so, you do not want them to "wash" the brick. They will likely use a pressure washer and all the sand will be washed away drastically changing the look of your brick. What's worse is that you and the guy doing the pressure washing won't even know the full extent of the sand loss and subsequent change of overall color unitl the brick dries completely. If you have this type of weathered looking brick, scraping the excess mortar off is the way to go. Or just leave it alone and let it add even more character to your home's facade.

I have heard different builders recommending different things as far as cleaning the brick--some wash it just where dirt and debris bounced up on it (around the bottom of the walls) and some wash the whole house. It's obviously much less expensive and less labor intensive to just do around the bottom. It may have been a cost cutting move on the builder's and/or subcontractor's part, or a miscommunication somewhere along the line. Provided you don't have a sand-faced brick, I would give the builder a call and inquire. If you have a sand-faced brick, I wouldn't let them anywhere near the house with a washer.

Hope this helps!