Email to Mobile

After checking on the O2 website this afternoon I've found that I can get a free email account on the o2.co.uk domain and then also get emails sent to that address forwarded to my mobile via sms. It looks like it is free too - I've not seen anywhere which says I have to pay for it!
You can filter the emails so you dont get deluged with sms's but the filtering system is rudimentary and badly worded. For example you can filter on sender equals, subject contains and attachment.
To me this implies subject contains the text string and the sender is exactly what you type in, then you will get an sms....not so.
The "sender is" really means Sender contains.....
Also if you put non alpha characters such as ! then the sms seems to get triggered all the time - probably because the ! normally acts as a NOT in logic.