Take the (as yet hypothetical) case we are arguing about. A corporate employee takes a piece of free software, removes the copyright and license and integrates the code into his own project. This employee has already shown supreme disregard for the original author's wishes by ignoring the (simple and easy to fulfil) requests in the license statement. Do you think said employee or his company would care if one presented a moral argument telling them that they were not being nice? I doubt that. Luckily there is a bigger stick, which is copyright law and which forces them to comply with the authors wish. Which is why I brought up legal liability (and just to be exact, "sneaking" was a quote from Morons post).

Actually, most open software licenses, including the GPL, allows you to take someones code, remove the copyright, and incorporate it in your own project.

Open software licenses put restrictions on the distribution (and legal precedence has established that 'distribution' means 'crossing the company boundary') of software. Open software licenses can't be applied to the situation you describe - they'd only get into effect if the code from that project is sold, or given away.