I received a physical mailing with a Spring Magic discount code (which we have used to book our trip back to WDW in May, 2020!) It's completely themed around the MMRR, with the phrase on the front, "It's a great time to RUNAWAY to Walt Disney World", and artwork from the MMRR ride.I posted somewhere before that WDW are actively marketing discounts between March and May with emails specifically using this promotion of MMRR opening.
There will be a lot of very unhappy people if it turns out this won’t be open for the duration of the discount. I realise things change, but if they had any doubt as to the opening date they shouldn’t have used the ride in the promotion.