Unless I'm sadly mistaken (and I'm sure F. Lee will correct me if I am), the standard in such instances is the exercise of "reasonable care".  For instance, with a name like "Smith, Martha A.", should one be reasonably expected to pull every possible variant and diminutive of that name?  Such an endeavor would be so time-consuming, we'd have to charge $250.00 for a Current Owner.

Just my take on things.

Regards,
Scott