I read where the cops asked him not to do the rally, so he opted to postpone it. Cruz doesn’t have this problem since he only attracts a couple dozen people at a hotel lobby. Cuz could probably IM them individually and set up a new meeting place in 5 minutes
I am fairly confident in assuming that the Secret Service recommended strongly against it given the number of protesters already inside the venue and the fact that some had already stormed the podium.