You could just swap out the bolts on the Yakima rack. Depending on how far you want to go, you can easily replace them with tamper resistant bolts or even tamper proof bolts.
I've been using Yakima racks for over 10 years even when I used to work at a store that sold Thule. I just never like the rectangular cross bars. With the LGT wagon, I really didn't like the integrated cross bar and towers of the Thule. With my Yakima, I did need new towers, but I can reuse my existing cross bars.