First let me say that I don't think anyone is entirely happy with the registration fee situation. Obviously the fact that payment is only by paypal is far from ideal. I'm not completely in agreement with where the registration levels were set. The website is confusing. But it's not an attempt to rip people off or discourage people from coming.
Let me explain the levels in a little more detail: there are three levels:
Professional: 225EUR (+ 16% VAT == 261EUR). This rate is for attending GUADEC as part of their job function.
Professional contributor: 150EUR (+ 16% VAT == 175EUR). This rate is a discount offered to professionals (people attending GUADEC as part of their job function) in various classes of people who contribute to GUADEC and GNOME: speakers, foundation members, employees of advisory board companies, and members of 'bwcon' (a local technological organization which is helping put on GUADEC.)
Student/hobbyist: 30EUR (+ 16% VAT = 35EUR). This level is for people attending GUADEC for reasons unrelated to their job.
We're not going to investigate who registers as a hobbyist. We want all members of the GNOME community at GUADEC, so if paying the the professional fee poses a problem for you in any way (moral, financial, typographic), please register as a hobbyist.
So, why charge registration fees at all? The basic reason is that plane tickets are expensive. While our sponsors largely cover costs like the the venue, if we take in more money, we can bring in more GNOME hackers from around the world. I think it's very reasonable to ask people for who are coming to GUADEC as part of their job to help bring to GUADEC those GNOME contributors that don't have a company to sponsor them.