What was interesting being in D where there were far fewer participants (only 24 took the start line and only 10 or so were really involved past the first lap) was being able to watch each individual rider a lot more easily and so being able to see who was actually taking part in the Series (and so knew the rules) and who had just decided to join a race for the hell of it.
Every sprint point was contended for by the same two or three riders out of the leading pack - I tried to either keep up with them or launch my attack beforehand (my 5 second power was massively lower than theirs, but my 15 second wasn't too far off) but apart from the one lap that I won, they normally just edged me out. Trouble is that meant even though I finished 3rd or 4th out of the 8-10 riders in our pack, I knew that the ones ahead of me were going for points and wouldn't be DQ'd or not on ZwiftPower, whereas the ones behind me probably wouldn't be registered, so I hadn't actually gained any points by trying a sprint compared to not bothering and just staying with the pack of non-registered riders.
Then post-sprint, you'd notice that the sprinters would all slow down to 1.5-1.7 w/kg until you at least reached the Volcano glass bridge turn off. Partially to recover, partially to let the main group catch back up to them and no doubt also to ensure that their averages dropped back below the 2.5 w/kg level (consider we were doing 75% of the lap at pretty much dead on 2.5, the sprint at anywhere between 4 and 6, so the remainder needed to be way under the limit). Those not sprinting must have wondered what was going on - why did these guys fly off every lap and gap the pack by 10 seconds, then just give up that lead to allow the pack to reform?
Of course, this is what caught me out on the final lap. On all previous laps, I had to put out a strong effort up the last climb (normally 3.2 would do) to stay at the front, but then it calmed down for a few seconds as the actual sprint itself wouldn't kick off until we were much nearer the line. This time however ALL the riders, including the non-sprinters were going for a stage win, so they went early and kicked at 3.7 on that climb (ironically the sprinters were probably less interested as 1st was only worth 6 points with such a small field, whereas each sprint was 5, so a total of 30pts had already come and gone). I noticed a second too late, then got stuck on the wheel of someone we'd literally just lapped and I found myself gapped by 3 seconds and growing. Put in a token effort, but ended up just cruising over the line as I knew even if I had caught someone, it probably would have been a non-registered rider anyway, so wouldn't have made a difference to the results.