Not necessarily...
You know, defending Sigung and his right to teach the way he sees fit or in the way that he professes to be "traditional" is noble as a student of his. I understand it.
However, I have been to quite a few tournaments (and, yes, participated in a number of them), and I have never seen a WL student (novice to expert) use mantis techniques. I've seen some consider it, but when the fists and feet start flying, it's a kick boxing match every time.
The problem with this, "It's my school, I'll teach as I see fit" perspective is that it is like unto sending a warrior off to battle with a plastic sword and a tin shield...when someone comes along with real armor and harmful intent...these kids, women and men are ilprepared --- and now, they're in real danger.
So, when a student comes to a Sifu and asks for instruction...when they are ready to learn and eager to learn and they are capable of learning..."hidden applications" or "you'll figure it out" or "go ask Sifu So-n-So" is detrimental...especially if you've already given them the responsibility of "Instructor". It goes back to finishing the job as a teacher. No, you don't spoon feed your students every little thing. You do stop holding their hands....but you will (or should) always be their guide. "Guidance" maybe becomes the practice, rather than "instruction".
...and a word on "Hidden Applications"....
Hidden applications are a farse...honestly, success or no, dead or no...there is no indefensible technique, so what's the point in keeping anything from your students? I can see no reason not to arm them with every possible defense...wouldn't you do that for your children?
...yeh-yeh...LIKE YOU DON'T CARE!