IMHO, it's a bad idea. First, there's no fallback for hardware without POT support. But the main trouble is that even with POT support, most video cards will use tricks to handle non-POT textures, and these tricks will lead, mainly, to performance issues but also to a few other disables features (may be RTT, filters, shader texture access, ...).
To make it short, most video cards handles non-power-of-2-textures like they handles non-triangles-polygons: badly
This feature may be useful while developing an application, but should be disabled for release. (enabled by a command line switch ?)