It's a serious issue and I know my T and pdoc expected full honesty concerning my symptoms from me, including suicidality, because without it their ability to truly be able to evaluate my safety and help me was greatly disrupted. Personally, I wouldn't take what your T is saying as anything more than a firm reminder to, in the future, continue to be honest if you are having suicidal thoughts. As in all human dynamic, consistency in doing this will allay her doubts about what you tell her about your safety. She can't work most effectively on only partial information, particularly if the client is deliberately withholding that information that is very important to evaluation.