Therapists as a whole do not handle these sorts of things in any sort of uniform or non-random way. It is, from my experience and reading, simply up to the whim of the therapist at the time. Some contact the client, some talk about it by bringing it up, some wait for the client to bring it up, some read ahead of time, some wait and read it while client is there, some try to get the client to read it to them.