I don't understand is it normal or it's time to create new django's ticket?
In [17]: User.objects.filter(pk=0)
Out[17]: []
In [18]: User.objects.filter(pk=0).exists()
Out[18]: True
The exists() should return False result in this case, I think. This is revision 11653 (Development version)
I have related problem with unique validating of inlineformset and I found that the reason is queryset.exists() doesn't work correctly