I want to remind you that when an employer asks such questions they're usually not out trying to discriminate against you, nor are they looking to "criminalize" anyone who doesn't mention a former name that nothing they're checking appears under. They ask because most adults (namely married women) who change their name don't go back and change every facet of their records like many TSs try to do, and they don't want to encounter a school or employer they can't verify because the name on their record is different (e.g. if they try to check if "Jane Smith" worked or attended school there and they have her record under "Jane Doe" then they'd say they have no record of "Jane Smith" and assume she's misrepresenting her history). For the sake of space on the form some don't go into further detail about what "other names" they're looking for, but it's generally held that unless it's a high-security job where they trace you back to birth, names that nothing they want to check would be under don't need to be put down. In the case of TSs, since they might have fears that they may use any technical omissions against them, that's where I got my suggestion of putting down that nothing relevant is under any other names if true simply as a way to "cover" yourself, and if they try to inquire any further that might invite potential legal issues in the case of discrimination (which is also why how they ask you about former names makes the difference; if they ask outright if you've changed [not the same as used]* another name, or ask only for former legal names as the OP worded the title, then that's strong evidence against the company in a lawsuit).
*Asking that way includes names that weren't necessarily your legal name (remember it's perfectly legal to use a pseudonym like a stage or professional name as long as it isn't fraudulent) that may be necessary to contact references, etc. and excludes names that were changed before you were of age (e.g. adoption) since when they ask if you've used or been known by another name they mean for something they're legally allowed to and are interested in knowing (e.g. if any of your work/school/criminal/etc. records are under another name) and not simply everything you may have been called since birth (otherwise some people would have to put down that they were originally "Baby" if that was entered as a placeholder if their parents were indecisive about their name when the birth was first registered).
ETA: In summary, they're not looking to penalize you for not listing every name you may have been known by in your life, but they can and will penalize you for not listing a former name that prevents them from checking and/or finding out information germane to the job qualifications.
