Verified answer

No.

C'est-à-dire que ton couteau doit être posé sur la table. (no subjunctive).

"que" is not always followed by subjunctive... For example, even if everyone thinks the opposite, "après que" is followed by indicative :

Après que je suis partie, elle est venue chez lui.

Why ? because "après que" present an action that is already past, so this is not an hypothetical situation.

But if you use "à condition que", you have to put subjunctive :

"je te prêterais mon stylo à condition que tu sois gentil" because this is a wish and a situation that has not happened.

Subjunctive is meant for expressions of doubt and wish, you are true. But "c'est-à-dire que" represents not this case. But maybe you have an example of sentence with it that is problematic ?

Subjunctive Dire

No, it doesn't.

C'est-à-dire que basically explains what preceded more precisely, the indicative is used here.

I am sorry I don't know about this

Non.

and anything that follows "que", so yes