Dont get offended – I am just trying to justify a big expense in though times like the ones now.
Your account of $1,500 for 3 days in Amsterdam would not even touch it. In May I will be shocked if you find a decent hotel for less than 200 euros a night (one bed), and when you order in Burger King – hold on to your hat 
Amsterdam is one of the most expensive cities in Europe, and I would like to see something tangible out of a huge expense, then just my peers opinion (which I get for free at this and other similar forums) or meeting them (which I could do for $9.95 at Chilies), or meeting an affiliate manager (which I have done, and yet they still left the US market).
Your company has provided very good speakers for other types of affiliate conventions, as far as I see, even “Representative Brian Patrick Kennedy (Chairman, House Committee on Corporations for the Rhode Island House of Representatives)” for your pharmaceutical conference for example. And yet, you have failed to do so for our industry (no offence, but I really dont see why I should pay for someones opinion when I get it free every day).
Also, I see only one company which provides sports betting, and it’s a well known fact that in Europe sports betting is 10 times more popular form of gambling than casinos and poker rooms…
The Professors’s arguments cannot justify such an expence by no means, however, since he is on the “Adisory board” (whatever that means) I have not expected any different reaction.
You have to understand that times are really, really tough right now, and you have to work much harder than usual to bring people to one of the most expensive cities in the world to listen to Dominique and the Professor (we do this for free here), J Todd (we do this for free every week), M. Corfman (we do this for free at GPWA) and so on… Not to mention that the comapnies which will speak on “SEO” issues could not be found on any search engine…