That actually makes sense. It's the smaller venues where everyone is in much greater proximity to one another where the issues seem to crop up.
Also, do big festivals actually provide WiFi? I have a friend that tours with Big Names and does IT and I know she sets up WiFi systems along with all the usual control networking for production, but I don't know if that's common practice or not.
Providing WIFI isn't always standard operating procedure. I've worked on some festivals where they set up access points at FOH and on stage and other areas. I've been on some where there doesn't appear to be anything about the show using WIFI. On shows that do have it, it seems that it's only used for convenience, and anything show critical doesn't end up using it.
As far as reliability goes, modern equipment does a much better job behaving in random places, but there's still the occasional situation where rogue equipment comes into play and makes a mess of things. Some wireless mics work great but destroy the wifi in the area. Other times, the working range is horrid, or if there's interference it's 2-3 seconds of dropout while it re-pairs itself.
It's just one of those things where avoiding 2.4ghz for mics is a better idea. If you're doing a low density project, say a mic for an exercise studio, that's a good use case for a cheap mic. On a live event stage, nope.
