My guess is that this is going to change once the parks open. They're not going to be able to enforce the rule with all the bus/monorail/boat traffic.
True but I wouldn't drive up to the security guard and expect to be let in without a reservation. I actually often do that on my last day. After I check out drive to poly for some tonga toast. I expect if I did that now I'd get turned away.
So I think they'll enforce it where they can (like the guard house).