Your school or organisation may not be large enough to put on a full scale fete or you only have the resources to hold the fete every second year. It is hard to get all the required volunteers.
The same applies on a smaller scale for street stalls. Often this also requires getting local council approval. There are also security concerns in handling cash in a busy street situation.
There is also the risk of bad weather.
Why not have a virtual fete by itself or combined with a physical fete? It could be set up in a similar for to our Demo Shop. People would collect the pre-ordered and paid for items from a specified location such as a school or community hall within a range of times. You could still provide some of the traditional fete experiences such as games, ice creams, fairy floss and coffee during those times.