She even threatens to call the police when the children talk about the day's events:
Jane: Oh, we couldn't possibly go to sleep! So many lovely things have happened today.
Mary Poppins: Did they?
Jane: Yes! When we jumped into Bert's chalk picture.
Michael: And we rode the merry-go-round, and all the horses jumped off, and-
Jane: And we all went riding in the countryside!
Jane & Michael: Tally ho! Tchunga! Tchunga! Yikes!
Mary Poppins: Really?
Jane: Mary Poppins, don't you remember? You won the horse race!
Mary Poppins: A respectable person like me in a horse race? How dare you suggest such a thing?
Michael: But I saw you do it!
Mary Poppins: Now, not another word or I shall have to summon the policeman. Is that clear?
It's unclear whether she actually can't remember what happened that day or if this is her subtle way of threatening the kids into not narcing on her ass.
Walt Disney Pictures"If you tell your parents any of this, you'll find out what's at the bottom of my bag ... and you won't like it."
Either way, drugs. Confusion, memory loss, paranoia, anxiety/nervousness, secretive behavior, mood swings, and changes in personality have all been linked to drug use. In fact, most of those symptoms can be attributed to meth.
She also begins to walk funny, say silly words, and refuses to explain herself in situations that would absolutely require an explanation. Look at this druggie's petulant meth logic run wild like a wolf under the midnight moon after Mr. Banks finds a gaggle of filthy chimney sweeps dancing in his house:
Mr. Banks: Just a moment, Mary Poppins. What is the meaning of this outrage?
Mary Poppins: I beg your pardon?
Mr. Banks: Will you be good enough to explain all this?
Mary Poppins: First of all, I would like to make one thing quite clear.
Mr. Banks: Yes?
Mary Poppins: I never explain anything.
That's the kind of response that leads to her being thrown out of the house and her throwing a brick back into it.