Comment by int_19h
I don't think so. As I recall, the different UI (not just from older MS stuff, but also from iPhone) was really front and center of Microsoft's pitch at the time.
Besides, WinCE PDAs were very much a power user / enthusiast device, with relatively few around. People who used them and thus were familiar with the old UI would be well aware that WP7 was completely different, and people that didn't use them weren't exposed to the old UI in the first place.
I think the issue was some people never even got around to seeing the different UI. They heard Windows + Phone and immediately thought of the older tech and noped out.