People are obsessed about working their notice or not. The worst that can happen is as follows
1. The company takes you to the Labour Relations Commission under the Minimum notice and terms of employment Act. The Rights Commissioner will find in their favour as you have not worked your notice. The company will be awarded no money however. I have never heard of a company taking a case to the LRC - there simply is no point.
2. The company will most likely give you a poor reference or not give you a reference at all. If you don't care about this, walk now.
By the way before the pedeantic pats point this out, they can also get an injuction against you in the High Court but this will cost them a fortune in legal fees. They would also win this