Well, both clinics and symposiums can over promise and under deliver.
Thats why its a good idea to audit before riding in one. Or at least doing a lot of research.
That said, as a thread on ring craft on COTH pointed out usefully last year, many riders lose points on geometry and precision that could be easily fixed. 5% would mean half a point on a move marked out of ten, like going from 6 to 6.5. At lower levels someone might do that just by riding corners correctly, having crisper transitions and a square halt.
And watching someone coach a training or first level rider trying to make the jump from 60 to 65: that could be very useful to some in the audience and just absolute bore to others 
What tips did you get?
Also clinician or symposium speaker can only work with whatâs in front of him, so some clinics might end up being pitched at a low level despite whateverâs promised.
For instance it might be a wonderful thing for the rider to move from a 58 to a 63 at training level, but like watching paint dry to someone who is thinking about 3rd level.