Around here, thieves use battery powered sawzalls. You can cut one of in about two minutes. Pickups and SUV’s are the target of choice because you can crawl under them easily. To slow these thefts down, you have to now prove you own all scrap metal to sell it. Not real sure how you do that. There all also smelters popping up where you can have different metals melted down. People are stealing man hole covers, drain covers and everything else not welded down.
The best deterrent for these thieves is to have them start considering alternative metals to collect such as inflight high velocity lead projectiles.