To answer Derek's question, all three councils have a hand in deciding or proposing traffic restrictions but traffic orders are done by DCC as far as I know. The control of Traffic Wardens has also passed to DCC from EDDC.
As for road closures and extra parking restrictions, very little is done in FolkWeek that is not essential - for example the ban on parking on the narrow road leading to the Bulverton car park. It would be chaos if this was not kept clear. Sidmouth is choked with cars all summer - indeed in FolkWeek perhaps less so than normal because so many residents stock up with what they need and don't come into town at all!
Dangerous driving causes many near misses in the narrow roads but that is the same everywhere in old towns that have not banned traffic from their centres.
The only stupidity I saw was the temporary road closure for 15 minutes at the end of Blackmore Drive (by the Cc-op) to allow the procession. It would have been far more sensible to have closed the road at the mini-island by Tesco (bottom of All Saints Road). That would have prevented drivers entering what had been made in effect a dead end. The steward on duty agreed it would have been more sensible - but the Traffic Order permitting the closure specified where the signs had to go. So blame the Council (DCC) for that one.
My own preference (going back many years to when I was a Town Councillor) would be for a largely traffic free town centre and Esplanade in summer. Chippenham centre is closed to traffic in daytime and is a pleasure to walk around during their folk event.
There are local arguments about parking meters etc and sometimes one council strongly disagrees with another - there was a proposal to install parking meters in Sidmouth's High St but the idea was quashed (for now).
The most common complaint I heard was that the clean and convenient toilets at the St John's Ambulance centre were closed all week. It was a staffing problem as I understand it. Several dance partners used to change clothes there. This year they had to make do with the area around the chemical toilets in the Blackmore Gardens - which was apparently revolting.
There was the usual farce of too many amplified bands around town and along the Esplanade, with amateur folkies being squeezed out.