This a typical PMP question because it gives you an answer that seems a little too good to be true. In this scenario, we've worked out our communication plan (meetings, presentations, etc) and method and we have an issue with the communication effectiveness. This is a natural place to put a new item in the issue log. The problem is, and many PMP questions will do this, is give you an enticing answer that is a little bit of a stretch.
For me, just because "Some have suggested" does not necessarily equate to updating the lessons learned register. Even though the suggestions are valid and seem common-sense, they may not necessarily effect the change. Perhaps there are too many people in the meeting (we need to break up the sessions), maybe the room is too large, maybe there was construction nearby.
Just my 2c.