Transcontinental Race (London - Istanbul) - #TCRNo4

That does add problems for organisers and crew through. Bearing in mind here that they run a checkpoint system on an otherwise free route.

Without the very minimal amount of vetting that goes on, just turn up and ride does mean that there's not a lot of opportunity to check that riders have familiarised themselves with a fairly simple and minimal ruleset and aren't going to end up causing a lot of hassle and arseache for a volunteer crew.

If you take a look at the sudden escalation in numbers for rides like the Dunwich Dynamo you can see how this could easily get out of hand. Even without any on the road support going on, an extra 100+ riders on the start line could easily turn an event like this into a logistical nightmare. The application/vetting process is as much for the protection of the organiser and crew as it is for anyone else.

Of course there's nothing to stop you from setting up your own turn up and ride event if you think that's how it should be.