Unless bogus SOS signals are a significant problem, they had a glaring red flag with lights, bells, & whistles. At the very least, get a couple of ski patrol teams to check the area where the SOS was found and then send a couple of seasonal interns to check the parking lot. Being able to link a car with a missing person report only gains you more detailed information (number, name, description, etc.) If bogus signals are a problem, start with charges of reporting false information to rescue personnel if you can track down who caused it. Maybe deferred prosecution in some cases but enough to get it through that it is no joking matter (give the judge a wide latitude between min. & max).