Not every company can maintain client-vendor relationships. Not sure if that's it, there can be other reasons. Yet 80% of lawsuits are company to company.
The open book has pretty much been a complete joke the past 8 or 12 months since the implementation of the hybrid market. Most of it is just fake size floating around. It really doesn't have the benefit it had a couple years ago. I actually cancelled my open book about 5 months ago and it had no effect on my trading except maybe a positive one. I guess it may still benefit a person that trades super thin stocks but not sure since I don't trade those.