At first glance, I can tell my prices are way to low.

There will be another photographer there (as a vendor); no idea of his/her qualifications as can not find a website or much on the internet about them.

Maybe a good alternate to on-site proofing is to use my 27" iMac to show the images shot at this event; kinda of like a running slide show that has no human interaction. Of course, that would require I quickly edit some images to put in the slideshow.