If you don't mind any damage to items below the washing machine or have no concern about the flooring then by all means forgo the pan.
Washing machine can overflow , hoses can rupture and a flooding happens in a matter of minutes.
The pan is just for safety "Do you feel lucky"?
10:51AM | 08/12/14
If the pan does not have a drain, and the drain is not connected to an exterior runoff, there is no point to have it. For one, almost any and all leaking will occur if/when a hose ruptures, and so most of your water won't even be in the pan. For another, if all you have is a pan without a drain, it will basically hold about a gallon of water; meanwhile, the other hundred gallons or so will still be on your floor. A washer pan without a drain is like using a thimble for a rainwater barrel on your gutters.