Glad to see that DL finally has someone monitoring the lavatories!

I usually hear one perfunctory announcement early on, telling pax to use the lav in their own cabin, but rarely see any effort at enforcement.

IMHO the curtain divides F from Y, so if you are walking past the curtain to use the lav, you are "trespassing". Having said that, I have to confess to that transgression...going from F to Y (but not in the reverse direction) to use the lavatory.

Although they say to use the lav in your own cabin, I think the real intent is to keep the F cabin free of excessive traffic.