In reality, national "reciprocity" will cause many to simply assume they can carry in the same manner as they can in their home state and some of these will get jammed up for it, for all intents and purposes losing everything, even if they win.
Whether they *ought* to be aware of the interstate differences is irrelevant. SOME will get screwed.
I've read the 2nd Amendment a couple times and STILL it does not say:
The Right of the People to Keep and Bear Arms Shall Not be Infringed, except where Federal, State or Local authorities impose limits, regulations or law prohibiting the ownership, possession or use of specific or general firearms, accessories, parts or supplies thereof.