Safe to use the SPs directly?

Hi All,
Is it safe to use the SPs directly on the default, Microsoft provided membership and roles providers?  If I look through the database, I see that it's created Stored Procedures for just about everything--create, update, delete all the different types of objects, like applications, users, roles, etc.
I'm working on a new project right now and I'm wondering if I can simply use the SPs directly during my development until I've got the UI for the app fleshed out enough to do things through that.
  -Josh

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