The problem is that there will always be some who are motivated by bright lights, instant fame and the money which can come with being a professional footballer. There's nothing which can be done to stop this.
Even if a player has been with Saints from the age of 8 and breaks into the first-team at 18/19 may have their head turned by a greedy agent or parent etc.
I'm sure we all know people in our work who are motivated solely by money.
Question comes to ask - do we sign a kid who's got all the talent in the world but is a cocky little ****, or do we sign on with less ability but a team player?