There are no guideline specific for charity tournaments that I know of.......they are regular SN tournaments and SN fees are paid. In the past you can ask the SN board to exempt the sn fees (it has been done in the past on a case by case basis) Not sure of the current boards policy though.
It was brought up in the past to exempt charity tournaments from having to pay SN fees but given the number of charity tournaments held each year the impact on the SNAC / SNPC was thought to be too great (at that time (a couple years ago) I think Ice Bowls made up about 10-20% of SN tournaments)
JOhn k