I can't comment on how events happen now, as I have no interest in going to them. However, while GM, I did have the "pleasure" of providing GM support for many official convoys. Most of my time was dedicated to spotting free roamers. This was quite an easy task, as I just relied on the TruckersMP map. I can concur that this wasn't something done by many GMs, though. A vast majority of them were either doing convoy control as part of the event team or dealing with more pressing matters, such as in-game reports. Thus allowing free roamers to pass through the net. Fixing this automatically is quite a complex issue, as there's many ways of it could be approached, all of which have their own caveats. For example, you could have an exclusion zone around the convoy route and anybody not driving along that route will either be teleported to the garage in the city of the start location or kicked from the server. This, however, has challenges in that you'd have to filter out staff and you'd have to account for people joining mid-route, nipping off to a fuel station and so forth. Bringing me back to my point that all solutions have caveats.
As for the route system, I think that's a great idea. It saves people having to rely on setting the route themselves and should hopefully resolve the problem of people getting lost. I'm not quite sure how it could be implemented to follow a precise route, i.e the one outlined for the event; however, I'd hazard a guess that there'd be a way of doing it using waypoints. Although, it's probably quite complex and far outside the scope of what the devs are willing to do at this time. That said, I'd like to see some variation of this in the future.
To touch on the GMs not handling free roamers once more, I'd like to point out that it's not that hard of a task. I usually managed to find & deal with quite a few without that much work. Hanging around population centres such as Calais, Duisburg etc... is the best way to find them; along with, as I said, using TruckersMP map.