Wikipedia: Mantrap (snare)

Mantraps that use deadly force are illegal in the United States, and in notable tort law cases the trespasser has successfully sued the property owner for damages caused by the mantrap. There is also the possibility that such traps could endanger emergency service personnel such as firefighters who must forcefully enter such buildings during emergencies. As noted in the important American court case of Katko v. Briney, “the law has always placed a higher value upon human safety than upon mere rights of property”.[5]

EDIT: I’d add that I don’t know about the “life always takes precedence over property” statement; Texas has pretty permissive use of deadly force in defense of property. However, I don’t think that anywhere in the US permits traps that make use of deadly force.