It's very unlikely that they would know, but do you really want to run the risk (however small) of getting a criminal record so early in your career? And there are one or two other things to think about... like what happens if you get sick? If you don't have a HKID card or employer's medical insurance then medical care will be expensive... Where will you live? Accommodation here is expensive (absolute minimum US$1000/month for a reasonable place of your own) - can you afford to cover that cost?
And probably the show-stopper is that your employer would also be breaking the law and subject to significant penalties if caught? Are they the sort of company that would be happy employing illegal aliens?