A law that simply requires tagging of spam or opt out lists will create an explosion of advertising email with no way for recipients to recover their costs. Faxed advertisements are prohibited outright unless the sender and the recipient have a preexisting business relationship. The TCPA has been upheld in federal court. It does not mandate an enforcement agency. No government agency will monitor email looking for violations.
Action occurs only when recipients decide they have received unsolicited email advertisements.
The TCPA may be enforced by the states or through a private right of action. The Smith bill would bring the same protection to email. It goes after the advertiser, not the agency, and US companies can't use offshore agencies to evade this law. The law targets the sender of the ad. Although some agent may distribute the ad, the advertiser will have to have its contact information in the ad in order to get any business.