We're not really IC's (at least in PA).
Do we get to set our own fees? No. *See below.
Do we get to wear our own uniform? No, the state dictates the uniform.
Do we get trained on our own? No. The state certifies, tests, and sends out training materials to all of the chapters.
Do we get to work the game the way we want? No. The state has a mechanics manual that must be followed.
Do we get to show up when we want? No. The game is at a certain time. They don't accommodate the game time to our schedule.
Do we control which games we work? No. We are assigned by an assignor who is hired by the AD's.
Meetings are mandatory (6).
Dues are mandatory.
The schools roll up to the PIAA, even though we get paid by the schools. Think of it in terms of the NFL. Tom Brady gets his check from the Patriots, but when they do the CBA, they negotiate with the NFL league office. So where you get your check from doesn't really matter.
Rememer, EVERYTHING is negotiable in the CBA. So anything you think "automatically" happens if you are found to be an employee or any "freedoms" you might lose if you were found to be an employee can be NEGOTIATED in the CBA. Want the right to decline games? Negotiable. Seniority wouldn't be in the CBA either. No official would want that.
State dues would be replaced by union dues. It's illegal to make an employee pay you for the right to work for you. Therefore, state dues are illegal. So, you wouldn't lose any money in that aspect. In fact, the projected union dues are actually less than state dues.
Now, with that being said, some states are different. Eg: New York, basically everything is done through the chapters and the state association doesn't really do anything. Indiana, officials actually solicit their games years in advance. So in those states, the argument for IC is much much stronger.
*The story with the lacrosse officials started because the AD's wanted to cut their pay by $35 for a double header (2 officials work the JV, then a third comes in for the varsity game). Lacrosse officials didn't want to take a pay cut (they didn't want a raise either, they just were happy with what they were getting paid). So they said we refuse to work the games. The PIAA then told their chapter president (the chapter covers essentially the entire western half of the state) that if they don't work for the pay cut set by the AD's group, then the PIAA will strip them all of their certification in all sports, disband the chapter, then make them all retest as new officials and re-do their background checks. So reluctantly the Lacrosse officials went to work for the pay cut. They then said this doesn't sound like something you can do to an independent contractor. Therefore they made the case that they were employees because of the control shown by the PIAA and won.