A good article from the Washington Post asking questions about TIPS:
Public vigilance is a good thing, and so is encouraging citizens to alert authorities to terrorist activity. It makes sense to educate people who work at potential targets or at places where lethal cargo may be smuggled. But having the government recruit informants among letter carriers and utility workers — people who enter the homes of Americans for reasons unrelated to law enforcement — is an entirely different matter. Americans should not be subjecting themselves to law enforcement scrutiny merely by having cable lines installed, mail delivered or meters read. Police cannot routinely enter people’s houses without either permission or a warrant. They should not be using utility workers to conduct surveillance they could not lawfully conduct themselves.
(via MeFi)