You do WHATEVER you and your fiance' want....it is YOUR wedding after all....
Alcohol has NEVER been a requirement for a good time at a wedding.....being around family, friends and celebrating your new life together as man and wife is what a good time consists of.
I would admit, that with a luncheon reception, the "pressure" to have alcohol is lessened, because people will less likely to expect it.
I would say, however, if you are inviting people that DO drink, at least have some type of alcohol available, as in a cash bar. There will need to be something for toasts, however....for people to pay for beverages to toast to, imho, is tacky.
Whatever works for you and your beloved is what will work!
BTB 07-08, luncheon reception with CASH bar....and a case and a half of champagne for toasts....