Fences
From British Juggling Convention Wiki
You will require fencing to give an impression of security, Herras fencing is 6½ ft (2m) high, comes in 10ft (3.5m) lengths and can be erected quickly.
It is not the most secure of fences as anyone with a spanner can make a gap (and during your BJC at least 2 of the jugglers who should know better, will do just that).
400m of Herras complete with base blocks and clips weighs 3/4 of a ton, so many volunteers can help here.