This is nothing more than the typical nonsensical tactics of WT. It becomes more absurd at conventions for some reason.
At the last two conventions I attended (at a WT Assembly Hall) there were huge sections of seats cordoned off with yellow tape. Roughly 25% of the available seats in the auditorium. I asked the attendant why they were roped off (because it's an area I normally sit in)? His answer: "I don't know, they just told me to guard the area and make sure no one sits here". An inquiry to the Convention Overseer got the same answer: even he didn't know why the seats were blocked off.
So, the seats remained blocked off and unused for the entire convention and we sat crammed like sardines into whatever seats were left over.
I think it has to do more with WT control than anything else. They do something that makes no sense, create an air of a big mystery as to why this or that is being done, and make it look official by placing guards to enforce the situation. It creates the mindset that WT/ the GB/ whoever must know something the rest of us don't, and who are we to question their 'wisdom'? There must be a good reason-after all, god told them to do it, right?
I suspect it often is nothing more than an experiment: how absurd can we (WT) be and the rank-and-file will still go along with it unquestioningly? Just how much can we get away with?
"Listen, obey, and be blessed"