From Mens Fitness Magazine: "Mistake #3 - Timing squats and deadlifts improperly.  These two exercises are the most taxing lifts on the central nervous system, especially the deadlift.  This [deadlifting] cannot be done optimally when you're recovering from a squat session." 

by Neil Anderson

This seems like a silly notion.  It might be true if life was about training.  Unfortunately (for these folks), squatting and deadlifting occur in nature.  Frequently this happens on back to back days - if not daily, or several times per day (farming, construction working, homemaking, sports, etc...). 

It is our experience at GPP that your major muscle groups can/must be trained more frequently than every 48-72 hours.  You were absolutely built for this.  It is also our experience that calling ANY movement that naturally occurs "wrong" is equally a bad idea.  Doing so exhibits a fundamental lack of knowledge, experience and functional understanding of what we are ultimately capable of and built for.