Tubbyengineer.
If you're looking for specific answers, then you'd probably be best off asking the organising committee directly, but good luck with that.. it would appear that their main objection to a stall is that they don't want the event 'politicising'.
Seems a bit thin to me given that if the political process of interpretation/implementation of the TPD isn't challenged, then all the vast majority of vapers will have access to are licensed 1st gen devices.
Can you see anyone wanting to attend an event to swap tips on how to get the best out of their 'nicorette lookalikey mk1' whilst browsing the 'vast' range of wares available from the half dozen vendors that are actually able to sell 'legal' products? That could be the reality of future vapefests if the regulations aren't challenged.
That's why it seems so ludicrous to many folk to not allow a stall promoting an important initiative that could help to challenge the regulations.
Matters haven't been helped by the arrogant, surly, 'fuck you, we're organising it and if you don't like it, you can fuck off' attitude displayed by some members of the organising committee. Granted, some of then put a lot of work into organising the event, but the main contribution of at least one member seems to be to just insult and troll.
As regards your point about forum members attending the event, it's my understanding that a lot of people who attend the event AREN'T active forum members (here or elsewhere) and are therefore, less likely to be familiar with EFVI. If this is the case, then vapefest could offer the potential to increase the amount of vapers signed up to it from it's currently disappointing 1% of estimated vapers in the country.
I'm at a loss as to why any vaper would consider this to be objectionable. The only explanation that currently seems to be on offer is that the organising committee seems to be on a power trip of some kind, view any suggestion that they don't agree with as some kind of affront and want to further that power trip by giving threats of cancellation of the event.
If the event has morphed from being about the vapers who attend, into being a power trip for the organisers then maybe cancellation might be appropriate.
After last night's shenanigans, I couldn't now give a monkeys if it goes ahead in it's planned form or not tbh.
If I want to enjoy the company of vapers that I like and get along with, I'll do it at small scale meets where ego stroking, affectations of martyrdom and shameless self promotions of folk as vaping gurus will be less of an issue.