How Clever! Now with the rainy spring under way I thought this was a brilliant idea. I already have a boot tray so I am off to the garden center to get some pebbles. :)
Make a boot tray by the door even better: Fill it with stones (found at garden centers). Ice and snow will melt and drain through the rocks to the bottom of the tray so your boots won't stand in a puddle. Most of the moisture will evaporate, but you should clean out the tray regularly.