Forum Moderators: open
May I suggest a different approach? Give the user enough time to browse your options, provide a "favorites" list to which they can add items they like, and retrieve later through some form of login. Once they are ready to order, they would choose from the items in their favorites. It's like putting together your own catalog - you only get the options you like, and then the decision process is a lot easier.
Respectfully, is it not always advisable to perform server side validation? Personally, I never trust session variables to be correct and always implement the validation server side - doesn't everyone else?
Granted, a form could be edited by the user, but you could also duplicate an online form and edit that too.