If my heater goes out, while its below freezing outside, and a salesman offering to fix it shows up at my door two hours later, whether or not its sleezy/ethically wrong is entirely dependent on how much they're charging for their services. I understand the angle that it could be interpreted as exploiting someone in a tough spot, but that's a no-more-valid interpretation than helping someone out of a dire, potentially life-threatening situation; it just comes down to how much they're charging.

The angle that they're finding clients by ambulance chasing public 911 records is interesting, but ethically neutral.