I was contacted by their HR department about two weeks after submitting my application, who gave me a date and time for the on-site interview. Though I informed her that I would be out of town for business that day, they demanded my presence non the less. As a compromise we agreed to a Skype call.
On the day of the interview, I cut my business short and I waited in my hotel room for over an hour for their call (yes, my Skype was on) but on one showed up. I then contacted the company to see what was going on. They apologized and blamed it on "network problems" and we agreed to try again (via Skype) at the same time the following day.
On the next day, I went back to my hotel room again and prepared for the interview. However, but expectedly, I received neither the call, nor any follow-up response from the company why they didn't make it to the interview. I found this behavior highly unprofessional as they simply didn't bother to honor their own commitment. To added insult to injury, they did not take my availability into consideration.
At the time of my application, this company received a number of start-up awards in Germany. Perhaps because of this, they developed a sense of pompousness and invulnerability. Perhaps, for them, it was already a great privilege that candidates were allowed to apply for work at their company and save the world.