You took the first step by monitoring your credit reports. I found something very odd in the course to clean up my credit. Creditors can do ANYTHING to your credit report. It may have been an issue of someone keying in an SSN wrong or it could have been something more sinister such as someone applying for a loan and giving their SSN one digit off hoping to avoid their own credit mess, or someone who actually has your SSN requesting credit and listing your as co-borrower (this happened to me without my knowledge. Luckily at the time, the joke was on them).
The bottom line is you are doing the first thing you need to do, keeping an eye out for changes on your report. I have had mysterious inquiries appear on my report, usually it was from an affiliate of a company I've done business with who accidentally ran a check.
Luckily the FICO does not take into consideration race, creed, species, disability or occupation or I'm sure I be fighting againt the fact that I'm a three-legged, pink hippopotamus who works as a stripper
The bottom line is that anyone can put anything on your CR the consumer must be very proactive the downside is that usually, its a losing battle.