It must be a Shadow Cruiser thing...they are the "entry level" trailers for Cruiser. I've got friends that have a 2011 FunFinderX and their's has the winterization kit. For $10.95 (or there abouts) you can get one and install it yourself. Darn site easier, and cheaper, than pouring gallons of anti-freeze into your freshwater tank. I hope you can get enough of it out this spring that you aren't tasting it come August...
I find it incredible that the bean counters would go that far though. I must admit though that my new 5th wheel doesn't have one either...at that "level of ownership, the builder expects that you will have the dealer winterize it for you" (according to the dealer). I ordered my winterization kit last week and I'll install it before this weekend. I winterize with air, but, I like having the kit installed in case something happens to my compressor and I have to use it.
My 2 cents, your mileage may vary...
2 Cats; J-Lo and Ragamuffin :R
2014 Thor Tuscany 40RX DP
2011 Ram 2500 Longhorn CTD HO
2011 Keystone Cougar 318SAB (now gone)
2008 FunFinder X 210WBS (Sadly gone)