I suspect this is all to do with Haitians and Venezuelans.
It should be noted that the flow of Venezuelans into the country has been reduced by the government requiring Venezuelans to apply for a Dominican tourist visa in Caracas prior to entering in the DR. It used to be that Venezuelan tourists didn't need a tourist visa solicited in Venezuela, instead they were automatically given upon arrival to any DR airport. What many Venezuelans were doing was similar to what many expats do. Enter the country as tourists and simply overstay. Unlike many expats, Venezuelans tended to overstay and never leave. Now is very hard for a Venezuelan to do that since they can't board a DR bound flight in Caracas without the tourist visa.
The regularization plan for Venezuelans was meant to regularize the illegal status of most Venezuelans and now requiring all foreigners living in the country to have a cédula is simply pushing the few that are still illegal to become legal, since a cédula is given to legal residents only.