I would be pretty confident that everyone who's been banned was identified and some action taken by the stewards inside the stadium on the night. Using CCTV to spot individuals where people aren't necessarily in their designated seat would be nigh on impossible, unless they are using facial...
I'd guess the difference was that at Marseilles, once we were deposited in the underground car park we were 'on our own' in terms of stewarding. Yes, we had the armed police to keep us company, but other than that we were in our safe space, behind perspex and netting, and we were allowed to...
I was at both games - I don't recall any beer throwing at Marseilles - from the state of many of the fans around me by the end of the match, ALL of the beer was consumed.
Possibly, who's to say? The club clearly want to stop this behaviour immediately, and therefore have made the punishment non-trivial. I'd be interested if everyone banned have been identified by Ajax themselves. I've not been able to find anything on the Ajax website about anti-social...