Spanish government Brexit contingency plans

The Spanish government is planning to pass a law (by decree) to give them special powers in the event of no deal between the EU and the UK. 

The Spanish law would appear to allow UK citizens to enter Spain without a visa after 29 March and to avoid the situation of (some) Britons in Spain becoming illegal immigrants overnight. The government would also be able to put in place measures to enable Britons to continue using Spanish healthcare, presumably through both the EHIC card (UK tourists) or the S1 system.