I agree with the others:
FIRST made a decision to use WiFi.
Way back when....before the cRIO...I recall many conversations about how great WiFi would be.
Okay so we have WiFi.
On the field side you have Cisco, on the robot side to date: D-Link and monitoring for the lot on 5GHz spectrum.
There is monitoring on the 2.4GHz spectrum but it's hard to enforce it because that spectrum is typically a mess.
On the high side of the 5GHz spectrum you have bands assigned to radar.
Luckily I've yet to see a FIRST team deploy 5GHz radar on a robot
.
That said: if there are multiple fields and you are in the 5GHz WiFi bands you should stay out of range of the fields (read - just don't do it). There are only so many channels in that 5GHz WiFi band and it's *extremely* likely with anything that can bond 2 or more channels (for 300Mbps or greater) you will short change the field merely by existing. Plus that can cause chaos with the robot radios as they are capable of discovering that interloper network.
Now the issue starts turning into this: Apple devices are increasingly happy to use the 5GHz WiFi spectrum. So ad-hoc networks between Apple users on 5GHz are point and click (and mind you that's not even for Internet). Per the Einstein report more and more mobile devices are using chipsets with 5GHz WiFi support. All of those can click their way into becoming an issue and per that report have become an issue (the details of that have been covered at length).
All that said: when I helped propose a 2015 control system I intentionally proposed a secondary low frequency radio for field related traffic leaving all the WiFi spectrums available. The entire point was to prevent the field safety mechanism from disabling robots because of radio link level issues. I proposed to do this using 3rd party modules with FCC approval attached to them. This meant that you could swap the hardware modules and the sockets were attached to the MCU in such a way that a very wide selection of frequencies were available below 1GHz. That meant you could accommodate radio regulators everywhere on Earth merely by swapping those modules. Mind the point that whatever was on the WiFi spectrum was no longer my concern. If a team wanted to use 2.4GHz on their robot for their vision systems it would not matter. If a team wanted to use 5GHz on their robot for their crazy Theremin controller not my issue.
As it stands FIRST (speaking as a 3rd party) has a vested interest in not altering the 2014 field system because they have end-of-life Cisco gear that is expensive and likely a pile of D-Link radios they can waste. Not to mention I noticed that last year antennas were changed which added some cost. I also noticed some additional changes in the way WiFi spectrum use was monitored.
I have, in the past, had to ask teams to turn off their 5GHz WiFi near the field. I will not say whom. There was a WiFi router with an open network sitting literally next to the field. Please just do not do this. You have bluetooth and other choices. Heck if you are clever you have infrared. Do not risk making issues on the field merely because you have zeal to do something interesting. Situations like the Einstein report need to never happen again and now that it has been investigated I doubt anyone will be able to plead ignorance of the risk.
In the past at the Mount Olive district event WiFi in the 2.4GHz spectrum was available but it was swamped by people with their phones and just shear demand. In reality the same bandwidth throttling technology now in use on the fields would help with that...but I bet very few events have any Internet available that actually has controlled bandwidth usage because that equipment adds cost (yes it can be done with a PC but most people just buy the finished product and have no interest in hacking it themselves). So with that all said: I personally am in favor of offering teams Internet access - by twisted pair ethernet in the pits. This has the distinct advantage of consuming zero radio spectrum unless the event coordinators decide to backhaul the traffic with WiFi. Still bandwidth controls should exist. However it should be much easier to reliably cap any team's Internet traffic if they are wired to the network as there should be much less risk of packet loss. For the teams this would mean they could use bluetooth or cellular near the field and dump their data at zero risk to the venue at the pits (these days there is way more than enough cheap storage to buffer up data in a smartphone).