I guess etiquette depends on your perspective. For me riding slowly at the back then I was pleased to find that the ‘elite’ were pretty polite this year as they piled past me. Not a great deal of arrogance from the ‘riders’!
For them I guess they would be more concerned about how quickly the elderly lard asses got out of the way and if I can speak on belhalf of the MNPR collective then I hope they found us very accommodating!
With regards to the ‘cheating’ I guess you pretty much only cheat yourself, but if your prepared to cheat then you take the risk of being caught… name and shame I say (or at least post a link to a strava activity for independent verification!).
Finally, anyone dumb enough to go through the start / finish had to bypass the ever increasing hoard of lurkers and deserves a ‘no placing’ for their schoolboy error! 😀