Yep, that's true - early withdrawals will close the account - but presumably that would be the intention anyway!Well you're not tied in for 2 years - you can withdraw the money at any time as far as I remember.
Anglo has a minimum rate guarantee of 4.5% on the RSA but that would probably be too low for most people to justify keeping the account open.
Personally I would be surprised if they dropped the rate dramatically - they seem to have been making efforts over the past few months to attract more customer deposits - raising rates on all their accounts despite the ECB keeping base rates on hold.