https://twitter.com/JhTV3/with_replies?lang=en
Short video on this twitter feed of a guy being escorted out - can see how tight the “crowd” is being corralled.
Ok... so the default value of 50 might have been a tad high for this rally but that’s ok. She can claim 50 even if she is under. If the cameras refuse to turn to show the crowd, the number is automatically 50.