Wrong trade entered into SGX

I read that a wrong trade was entered into SGX, which caused the ST Index to drop by 400 points.

The traded wanted to sell DBS warrants at 27 cents. Instead, the trade was entered under DBS (which was traded at $24.00). The trade was done.

This problem could have been avoided by a simple check in the SGX computer system. Every trade should be checked against the last done price. Any difference of more than 5% (say) should be highlighted for the trader to confirm the trade.

If the difference is more than 10%, perhaps a second re-confirmation should be required.