a droid w/o a data plan essentially becomes a media device. you can still use it on wifi for things like web surfing, email, multimedia streaming, etc but you will not have 3g service for when you are out and about
yes really, there is no way that i am even peripherally aware of to "fool" the network into thinking your droid is authorized to use carrier provided data services.
even if you unlock it you need a network to connect to. Once the phone company finds out you're using minutes without a data plan, they'll add it on for you