More cat advice sought. (Warning: Poopies.)

Ada's taken to going to the bathroom in incorrect locations lately. Last week she peed on the rug next to her litterbox. Yesterday she did her number-twos in the laundry basket in our bedroom.

Becuase she is stealthy, we don't discover the accidents until long after they're perpetrated, so we haven't bothered punishing her. But we'd like her to cut it out, just the same.

Thoughts of things we might be doing wrong, or which we should be looking out for?