Just my experience with CD so far... and just a story no points to be made here.
A few years ago I got a call from an old buddy in Qld and told that i have to come to CD7, I quickly scoured an internet sale site and found my dream enduro mount an 87 WR400, did a resto in a couple of months and just prior to the event I found out about the pre85 rule. I called VMX and pleaded my case and they said fine come along.
Next year I convincd my brother to come along, he didn't have a bike and I had 2 , so i lent him the 87, he rode (thrashed it, the pr$k) all good, no comments from anywhere.
Last year i dragged 3 of my Huskies to CD9 including the 87. Wasn't really going to ride it as I had just purchased the AE. As it turns out my Boofhead brother blew his bike up in the first few minutes of CD9, so he rode the 87. I did on lap of the enduro course on it. All good no issues, nil comments.
As far a s travel goes on bikes, my XC250 has 12" front and 13" rear which is more than my 3 later model bikes. Just sayin...
If someone is outside the rules than I suggest you call VMX Mag to discuss the issues with them.
(the 87WR wont be making the journey this year, which is sad because its a wonderful old bike)