I haven't used polo wraps or boots in years, as I'm not convinced that a little bit of cotton or neoprene or whatever offers much support to a 1200lbs (or more) animal, which is of course more than 1200lbs if you also consider the force with which it's landing on each leg. I did some research on the effect of wraps and boots when I got tired of wrapping polos and found that this has indeed been tested by scientists, and the findings of their studies suggest that they do not offer any significant support to the tendons and ligaments.
My horse is also very careful with her feet and never interferes with herself, not even in lateral movements. If she did, I'd protect her legs with something. Otherwise, I don't see a point.
Not sure if you've seen an over reach injury, but they're not nice and take a long time to heal. I'd rather boot/bandage to protect against these sorts of injuries that can be very easily prevented
And yes, in an ideal world a horse will be so perfectly trained and its balance so impeccible that it will never knock its legs. But this is not the case more often than not - young, green unbalanced horses, horse's learning laterals, horses begining collected and extended work....