T-Mobile Web 'n' Walk - Unlimited 3G Access

I've just had a look at the Register's article on T-Mobile's Web 'n' Walk tariff. Allegedly it's £7.50/month for unlimited 3G access.

...although the service is "unlimited" there are restrictions.. so it's not unlimited then?

Also on the T-Mobile site:

*Minimum term contact and credit check applies. Compatible handset required. Fair use policy applies: Relax + web 'n' walk and Flext + web 'n' walk price plans provide unlimited internet surfing on mobile handsets in the UK. To ensure a high quality of service for all our customers, they are not to be used for other activities such as (but not limited to): modem access for computers, internet based video/audio streaming services, peer to peer file sharing, internet based video download and internet based telephony. If such use is detected, notice may be given, after which network protection controls may be applied which will result in a reduced speed of transmission.

It's unlimited Internet access but you can't use if for downloading video, downloading streaming video and music, IP telephony and file sharing?

I think the point is that with portable devices becoming more and more powerful and coming with big storage space, then people are going to want to use it to download big data. But this access isn't available?