Working for yourself requires a lot of sacrifice and a desire to handle all things for yourself. This is not some admirable goal. Rather, it's an option for people whom it fits.
I work for myself and I definitely don't recommend it for anyone who wouldn't refuse my advice to work a solid salary job. =)
Laravel isn't the kind of framework to lock you into a specific way of doing things. It's different than what you may expect if you're coming from Symfony, Kohana, CodeIgniter, or Fuel.
There's no reason to tie a validation system into a model. That's enough justification for it not to be done. You have the flexibility to implement it easily in whatever way you see fit.
I work for myself and I definitely don't recommend it for anyone who wouldn't refuse my advice to work a solid salary job. =)