To get "sucked in" to an earlier wave, i.e. it happens by accident - I'd say no, it's not easy to do. To deliberately do it by turning up extra early and just queuing up wherever you can in your colour's start area - then yes, that's quite easy to do and I'm sure a lot of people do.
However, I personally wouldn't do it - not because you'd get caught (you won't, none of the marshalls care), but because the organisers have gone to great lengths to try and space out the field so that everybody doesn't hit the big climbs/narrow roads bit all at the same time. And I know you'll say I'm just one person and it's not going to make a lot of difference going an hour early, but as soon as everybody says that, it does make a big difference and the climbs are busy enough as it is already.
Having said that if you do want to start early, your official time is solely based on the timing chip that activates when you roll across the start line and finish line and has nothing to do with what wave you started in (or were supposed to start in), so there's no worries there.