Speaking Japanese--what's your policy?

I'm really of two minds with this one. On one hand, I think that switching to Japanese for a few sentences here and there in the classroom to illustrate a point or for directions really is necessary to keep the flow of the class and to prevent the students from shutting off because they are lost. (No JTE in my classroom) Instead of miming "Open the textbook to page ten" over and over or forcefully pointing behind you to show 'yesterday', just switch to Japanese. Also for discipline and encouragement--the 'please put that away' and 'I think you're really improving' type of thing, instead of body langauge and super simple English.

And being able to communicate outside of the classroom might be helpful in creating trust/bond and to be looked at as less of a dancing monkey and more of a teacher.

But the other half thinks that total immersion in the classroom is really the way to go. You're not teaching grammar anyway, and who knows how to say reflexive pronoun or subordinate clause in Japanese? If they know the ALT speaks Japanese or will revert to Japanese if they push, they won't try and therefore not learn English as well. And if you speak Japanese, it's opening up a can of worms because you will get in conversations that involve hard words are just way too difficult to hold. And don't most BOEs want ALTs that don't speak Japanese, so the students will TRY and communicate in English? You'll lose your novelty and therefore effectiveness?

In my case, my students know I speak a decent amount of Japanese, but I never use it in the classroom. If they ask a question for clarification in Japanese I'll answer them in English, but sometimes I really want to switch to Japanese because it would be so much easier.

edit

words