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)
According to the Ice Bowl website (http://www.icebowlhq.com/), you do have some requirements to meet in order to use the "Ice Bowl" name.
We require that all tournaments that use the name "Ice Bowl®" raise money and/or food for a recognized charity, ideally one that helps fight hunger. In other words, if you are not interested in charitable fundraising, you may not use Ice Bowl as part of your tournament’s name.
They don't give a whole lot of info on their website.