That may be, but it doesn't change my suspicions. It is pretty easy to create a sample little script to do something/anything and share it on Github or Bitbucket.
I would think this is the rule actually for most clients. At best you can just use their name and say "I worked on building this project ABC at client XYZ". That's why Google etc wants a face-to-face interview or at least over Skype so they can ask you their infamous programmer's questions on the spot.
One can always find reasons to fail. A portfolio with for-hire projects demonstrates a range of experience. A portfolio with personal projects should show range and depth of skill set. Honestly, I have never, ever been asked stupid trick questions in a consultation/interview. The first question is almost always "Tell me about yourself", followed by "We have looked at your portfolio, and let's talk about it". I don't associate with a lot of other freelancers though, so my experience may be completely unique.
Based on my experience, I would recommend to Glumanda to put together some sample code to share on Github. It doesn't have to be a big or complex code. My portfolio contains a stupid little log-in form where I was playing around with shadows and text. The level of effort to put together a small portfolio far outweighs the effort required to get people to pay attention to what you have to offer when you have nothing to show.
Min