I mean how hard would it be for SHIELD to research and keep tabs on enhanced vigilantes living in New York in 2017? SHIELD has been able to crack highly advanced prosthetics that work just as good if not better than an original limb. You can virtually not tell at all anymore that Coulson's using a prosthetic hand. They reverse engineered SHIELD helicarrier cloaking technology for the Quinjets. They invented Night Night Guns. They made those flying escape pods and holding cells. So you would think they could figure out what's going on with these enhanced types and if they are a danger or of interest to SHIELD or not.
I'm not saying they will be forced to register. But at the same time, after the way it's been handled, it's not something they can ignore forever. Technically, the likes of Daredevil, Luke Cage, Jessica Jones, would all fall under the Sokovia Accord legislation.
I'm not saying they need to do a full-on SHIELD crossover. But some sort of visit from Coulson to say he knows who they are and he is keeping an eye on them. Maybe he even advises them to keep their profiles low in order to protect them from the Accord laws. But it will have to be addressed at some point.