Teachers at our school are now allowed to walk into our toilets when ever is this legal?

The legality of teachers entering student restrooms typically depends on school policies, local laws, and regulations regarding student privacy and safety. Generally, schools may implement such policies for safety reasons, but they should also consider students' rights to privacy. It's important for schools to communicate these policies clearly to students and parents. If there are concerns about this practice, it may be beneficial to discuss them with school administration or refer to local education authorities for guidance.