It could just as easily have been one of the other diners.
Doubt it was another diner as it happened so quickly. Possibly someone taking reservations? OR, since we now know that the FBI etc. spy on their political opposition...maybe it was them...lol. It was very well organized.
If you watch the video, the staff really DID try to help...as Sen. Cruz was asking the scum to let his wife through, the staff members were standing right there trying to escort them out (there were at least 2 employees in the vid).
Looks like a nice restaurant; how did those freaks get past the front? The other diners are very well-dressed while the screamers look like vagrants. Perhaps the same person who took the reservation let them in?
Not as easily.
If the fascists live near Fiola, they are rich fascists -- not likely. They probably had to drive from their home base to Fiola, find nearby parking, and walk to the restaurant. Parking can be a time-consuming nightmare in D.C.
The fascists might have had plenty of lead time if they were tipped off by a Republican-hating Fiola employee who noticed a reservation in Ted Cruz's name, particularly if it was made a long time in advance. If instead the fascists responded to a tip from a Fiola diner, they had to move fast.