Should the heavy hand of Government decide? Certainly Not, especially if the agency is funded by the decision. Should the civilian courts decide? I think they're choked up as it is, and you can be sure that would lead to huge legal expenses just to defend ones-self if a rescue is legitimately needed. Should it be covered by the boater's insurance policies, like private tow and salvage? That would keep even more people off the water, as insurance rates would become prohibitive for MANY.
I see this as being similar to the rescue fire/police/ambulance on land, with the government bearing the expense. I think that's what Government is for... to benefit the general society in ways that aren't feasible by "for-profit" or privately funded non-profit organizations. PLBs and EPIRBs are affordable for all boaters and greatly reduce the cost of SAR by reducing the search element, and I do think it's reasonable to legislate that people who don't carry such devices be charged for at least a portion of the search portion of the SAR. But then you open a can of worms about what if the owner didn't maintain the battery or carry the device, or if it was lost due to circumstances beyond control etc.