Tell me about your first day of training..

[HighKick]

So you tell your students not to practise between classes in case they somehow ingrained ‘imperfection’? They should only practise before a teacher who can correct them? Have you heard of homework set be teachers and lecturers throughout the world?

Of course not. But have you ever had to help someone 'unlearn' something they were taught/learned wrong? It is usually quite a process. Like putting a lefthand bolt in a righthand thread.
I expect students to practice on their own but stress great caution about working on the techniques they are at least familiar with. Who expects a white belt to ever do their first form 'perfect'?
How many people have you seen go full strength/speed from day one?