How many of us in the industry derive our sole income from our haunts only? If that was the defining factor, the number of pro haunts would be super small, even the amusement park ones since the staff dedicated towards the haunting side is very few. For example, Knotts has a staff of thousands of people, but only one or two actual people who have it as their full time job dedicated to the haunt side.
For example by definition, Larry would be semi pro and not a true pro since the majority of his income is defined by sales from HPI rather than solely the haunt.
Jim Warfield would be one of the few entirely pro haunters as 100% of his income is derived from his haunt.
The permits and insurance and business aspects make a good defining line.
The word for the day is NPD. Check it out.