To the best of my knowledge, everyone wears (or at least is authorized to wear, shortages aside) their trades cap badge on completion of basic training. We have trade badges to indicate training level.
Of course, you're welcome to your oppinion, but I don't see anything to be gained by with-holding it. If anything, giving it on completion of BMQ starts building identity and brotherhood out of the gate.
At what point would you consider somone to be a "true" sig-op (or any trade for that matter)? If we're going to move the bar up, we might as well set it high... from now on, no one is considered a "true" sig-op without at least 9 operational tours, with no functioning testicles (and/or ovaries) due to RF radiation exposure. As further proof of your loyalty to the branch, prior to receiving a hat badge, "VVV" is branded into your forehead, and you're required to get a large jimmy, surrounded by cadpat, tattoed on your shoulder.
I was going to go somewhere with crafting your own winged sandals, covering your body in gold leaf, and climbing mount olympus, but that seemed excessive.