I noticed in the "text/phone game" (perfect guide) this step about the guy never giving his number but always asking for hers, but I am unclear as to the rationale. I assume that this means never just giving your number and not getting hers? Or is this deliberately saying to not give your number in the exchange?

Usually, when I have a girl interested and she wants to go out, I ask "How do we make this happen?" (advice I got from this /r), and she offers her number. At that point, I pull out my iPhone, set up a new contact and then I hand her my phone to put her name and number in. She happily puts in her contact information. Usually, I then call her on the spot so she has my number (she pulls her phone out of her purse). I do this solely so she has my number and knows when I text (I have no insecurity with getting a fake number). I hate starting the first text with "Hey this is "egoherodotus" from the bar last night, ........."

Is this wrong?