My concern is that the only remedy to such "ad hoc meetings," that I can see, is censorship.
A) There was an ad hoc meeting, which prevented people from choosing to attend. I'm not implying malice here, but again, irregularity. And it is these kinds of irregularities that may be fostering the sense of mistrust in the process among some members of the populace.
For example, if I am at an event, at which no meeting was planned (or outside of normal meeting time), and someone asks me something related to the transitional business, then my options are to answer plainly (which creates an ad hoc meeting), or to refuse to comment (on grounds that discussion outside of formal meetings is prohibited).
I don't think that such a prohibition is supportable. People are going to talk about stuff, when and where they're able. So long as those discussions don't rise to the level of making official decisions, I think it's reasonable.
And that's ALL I'm going to post today, I promise!