Not sure I agree with the terminology "right" to open carry, but I think I understand where your instructor was trying to go. As a delaware resident, (correct me if I'm wrong.. only DE citizens can open carry in DE???) you can open carry a firearm without any type of permit with the exception of certain towns or cities that have special "rules" against it (such as Dover).
I personally think open carrying to getting used to carrying isn't the best method, but to each their own. I'd carry concealed in my own home and learn by doing what works and doesnt work for you. Again, just my .02.
Read the updates on deloc.org and draw your own conclusion regarding if they get hassled, etc.
Moosie