... If you register with a “2018 Winnebago” they won’t bat an eye. Try registering to camp there with a “2018 DIY MagicBus” and see if they have questions.
I don't know where you visit, but I have 20 years and well over 100k miles traveling all over North America and not once did I register in a CG as "2018 Winnebago". 100% of the time is was 32' no slide with 30 amp, or 36' with slide and 50 amp, or now, 24 foot no slide with 30 amp. Not one single CG in the US or CA ever asked the make of my RV or if it had an RVIA sticker.
Dave