I've heard that too but that wasn't the case with my puller! He rarely pulled in his harness (it wasn't the anti-pull type) but was terrible with his collar!
The only trick that worked with Dodger was stopping and ignoring his pulling. After all leaders are calm, not anxious or frustrated. So when he realized I was going to calmly wait until he did what I wanted, he was brought down a notch in the grand scheme of things! It didn't happen overnight - keep at it and your dog will master it!
Moo-goo: I found the same thing too - Dodger could do all this great competitive obedience and agility stuff but couldn't do a simple everyday thing like go for a leisurely stroll!!!
