Many more decutions would be available....office space within their home, home telephone as well as cell phone, an answering service, etc look at what is available for a small at home business.
You made some assumptions that are incorrect.....they are not independent contractors and do in fact have an employer. A ref works for associations ie GTHL, OMHA, OWHA and can not ref games unless asked to do them by these associations a OMHA or GTHL has to pay a transfer fee to ref OWHA games to the OWHA. They do no simply look on line and assign themselves games. Next many refs are not paid in cash and are paid by cheque.
Lets look at a paid volunteer: Your words they are paid a set amount....yes they are! They are given an reasonable amount to cover expenses.....yes they are again.
lets look at a ref who refs a game in the evening....they are assigned a game that is a Midget AAA game which starts at 8pm. they live 30 minutes away from the arena and need to be there a minimum of say 30 minutes before the game. So they leave home at say 6:50 pm and drive to the arena. They ref the game which has a couple of major penalty calls. The game is allotted an 1 1/2 hours of ice time but is delayed in starting by 30 minutes. So the game ends on time at 10pm. Then the ref has to write up the game on the white copy as there are some major calls on the game sheet this takes about 15 minutes then a shower and drive home and they arrive home at 11pm....they are gone from home for 4 hours and they are paid $40 for the game......seems more then reasonable to me!
Even if there was no delay you are talking about 3.5 hours of time commitment for one game....wow refs are making a killing!
They are paid volunteers.
Play hard, play fair