This is a valuable discussion of an important topic that needs to be resolved.
I agree that the group should be fined. A fine in these instances is a "stupid-tax" that may help people think, plan and decide better next time. We recently had a young teenager from Alaska die in the Phoenix area from heat while hiking up a city park mountain. Sad, and so unnecessary.
Those who weigh the risks and are willing to take them, must be willing to accept the results if things go bad. Paying the bill for rescue is one of the results that are predictable, even if the odds are low.
The fire dept. analogy is a little off target. We support FD's by paying taxes, whether we use their services or not, because it's cheaper than paying all at once if we use them. If the fire is our fault, our homeowner's insurance may not cover the damage, and if arson, we'll go to jail and pay big fines. SAR does not usually receive direct tax funding, but are mostly volunteers supported by donations. We have no insurance, either, for mishaps in the wild. If we go out in the backcountry and make bad decisions, we should pay the bills of those that save our bacon.