When a thief submits a fake tax return in your name, it doesn't matter whether you actually owe taxes in real life or not. The thief will make up numbers and claim a refund. The IRS typically sends out refund checks before verifying that everything claimed on the return is accurate. It is later that the IRS goes through each return and decides which returns need to be audited for accuracy.
So the amount on your W-2s is irrelevant for the thief.
Remember, if this should happen to you, the thief has not stolen from you; they have stolen from the U.S. Government. You are not personally out this money, and you will still be given the opportunity to file your correct tax return.
As mentioned by Michael in the comments, some scammers were using FAFSA's IRS Data Retrieval Tool to obtain W-2 amounts to provide more accurate information on the fraudulent return. Currently, the tool is disabled while they work at making it more secure.