In other words, if you want to hijack the ride and take it to the destination of your choosing, all you have to do is ride to the front of it.
That's an absurdly alarmist interpretation of the term "hijack", is it not? It seems to me that your description perfectly ties in with DZ's point that it's a not-terribly-organized affair where people have diverse aims and motivations and it's not always terribly clear what, if anything, is going on. This ties in with most protests I've ever been on, which are often aimlessly amiable affairs affairs where occasionally there's a frisson of interest when someone appears to be doing something purposeful, only to die down again when everyone realizes they've been following some bloke on a tea tray who's gone off for a pint of milk. I can only repeat DZ's appeal for everyone to chillax...