Use your genderized bathroom

So, a situation of boys using the girls bathrooms:

Hello Gentlemen,
It has been brought to my attention that someone has been using the Female Facilities (bathrooms) in the Residence Halls. You were placed on the Male Floor as you listed on your application that you are a male. If this information is incorrect or if you do not find the facilities up to your standards or the facilities do not meet your gender orientation needs, please contact me. If the bathrooms on the male floor are dirty, please contact the security desk and/or conference services.
Thanks!

My supervisor said I shouldn't send that, the one who is breaking the rules might find it offensive, so, first edit:

Hello Gentlemen,It has been brought to my attention that someone has been using the Female Facilities (bathrooms) in the Residence Halls. Stop it.
Thanks!

It was then brought to my attention that I forgot to mention that the residents could get kicked out for doing such a thing. So, third and final edit:

Hello Gentlemen, It has been brought to my attention that someone has been using the Female Facilities (bathrooms) in Residence Hall. Improper use of the facilities in the Residence Hall can result in your dismissal from the residences. You are still responsible for any financial obligations that are in your name. Please let me know if you have any questions. Thanks!

This of course led to a few emails back and forth with a former RA on the floor not understanding.

Student: I don't understand. We are on a different floor, we are group together...

1st 5: Boys are using the girls bathroom

Student: LOL. What

1st 5: Exactly! I knew a RA would be outraged by this!

Student: Couldn't have been any of us... we have a bathroom on our floor.

I still don't think he fully understands at this point and explained that he could go visit the girls on the floor below, which he stated he does not do. I might point out that there are three boys in summer housing...