AIUI the ASA was referring to peak traffic management. If they actually meant that it's OK to cap a user for going over an arbitrary level on an "unlimited" account then they need a rocket under 'em.
It's worth noting a few things:
1: The ASA actually did something. Ofcom and OFT have both been studiously ignoring complaints about "unlimited, oh not really" shit since time immemorial.
2: The ASA is a trade association. Ofcom and OFT are govt departments
3: Ofcom (in particular) is full of people marking tim until they nove onto jobs in Telco/ISP management. Make of that what you will.