I understand your point and generally, you are right, however, this behavior is too complicated through the different Operation Systems, browsers, cultures, etc. Basically, the problem is that there is no defined standard which we can follow - in some configurations the new row char count is 1 and in others - is 2 characters. The chosen behavior can be appropriate to some users, and can damage the logic of others.
Nevertheless, you can log your requirement as a feature request so our developers will consider including it for the future releases:
If you want to get updates on new releases, tips and tricks and sneak peeks at our product labs directly from the developers working on the RadControls for ASP.NET AJAX, subscribe to their blog feed