Confusion on accrual concept and revenue recognition???

There is a question which goes like this : K company's revenue of $380 m in its TB includes goods sold and dispatched un sep 2011 on a 30 day return basis. Their selling price was 2.4 m and they were sold at gross profit of 25%. Keystone is uncertain whether any of these goods will be returned within the 30-day period. How should k company deal with its published a/c at 30.9.2011??? The answer is explained and given as; Whether there is uncertainty over goods sold on sale or return basis they should not be recognised as revenue until they have been formally accepted by the buyer. I.e Dr inventory 1.8 m$($2.4x 75%) Cr COS 1.8m Sir my confusion here is why didn't we follow the accrual principle and recognise the sale as soon as it has happened instead of waiting till the end of return period ??? And record the transaction as : Dr revenue 2.4m Cr recieveables 2.4m