Pretty much what Brad said.
Also, most people are predictable, so if you watch someone for a minute or so you should be able to know what they're going to do.
When people stand still, they're probably using WM or counter. If they're walking, they're probably using defense. If you fail at pvp, you fail at pvp.
QQ and get over it.
Actually, alot of peeps walk while using smash nowadays