I love people who request something with lots of colors! This sign was designed for a brand new home that the owner wants to keep in tip-top shape.
The owner of this sign wanted it known to visitors that she really loves having you there, but to please respect her investment by removing your dirty shoes. I think with the bright colors and teaming the "Remove your Shoes" portion with a "Welcome" sign is sending a polite message without sounding anal.
Congrats on the new house!