This week I have done one mass start race with drafting turned off (noticed pretty soon from the missing “Close the gap” messages) and another mass start race with TT bikes. Plus enough races with men in the women’s category (“Women only” flag missing) over the last couple of months that I’ve lost count.
All of these can in principle be seen at least on the events web UI after clicking on the “Toggle event details” thingy but I guess there’s no effective way to report such irregularities before the event? (The events can only be edited by Zwift staff, right?)