Calling it unethical sounds excessive to me. After all, offering a fake profile of oneself is just a harmless joke. I'd rather adhere to your expression "it goes too far". Many online businesses do handle personal information with care, I wish to think they try to separate profiles from people identities. I mean, they should have designed their systems to record who migth be interested in, say, luxury cars and being able to display targeted ads to them, while preventing anyone to know their names.

Not all web sites are make equal, however. Whilst I think it may be unfair to lie to a respectable business, I am sure there are many others that really deserve.