If your bx/gf is strong enough, she won't be easily corrupt by those sisters working as WL.
I do not know why many bro are worried about letting bx / gf mix with her friends who are WL.
I let my bx mix with them.... They are a source of income for my bx
They earn money easily and so they are willing and big spender. My bx treat them well and show a big sister love to them but when they ask my bx for help... My bx will whack their pocket and put in my pocket