There are approximately 465 cameras in the Etihad
There are databases (supporter info) that allows people sitting in seats to be identified
However you must remember that people swap seats sell seats move seats
It would be possible to identify say 80 percent however
You have to be proportionate every person who runs on the pitch commits a criminal offence there are more serious offences such as criminal damage (doesn’t have to be deliberate TH it can be reckless)
Flares and racist behaviour etc etc
The police and club will have had to make a policy decision on who and who not to prosecute
Also the persons previous character will have implications (some may have received other forms of disposal caution / fixed penalty)
Please also be aware that the club will be a massive driver behind this
It’s not solely the police