Realband will try to access things in the BB folder, but I'm pretty sure the opposite is not true.
In Other Words, I think you can install BiaB without RB, but trying to install RB without BiaB would be problematic, or more likely impossible.
If worried, just rename the folder first .. if nothing blows up you can safely delete it.

I say this because I have installed older versions of RB and it didn't affect BiaB at all.
.. and also from a bit of beta testing knowledge over the years


Make your sound your own!
.. I do not work here, but the benefits are still awesome