Is a person sinful for creating a page to teach henna tattooing if one of the students learns from it and displays the tattoo in front of non-mahram men?

"Henna engraving on the body is permissible for women, and the basic principle is that assisting in it and teaching it is permissible, except for someone who is known to use it for unlawful display. There is no objection to opening a page to teach women henna engravings, and it is good to alert on the page not to use it for anything forbidden. There is no sin on the page owner if someone benefits from it in a forbidden matter without her knowledge."