[belorn]

provided that you conspicuously and appropriately publish on each copy an appropriate copyright notice; keep intact all notices stating that this License and any non-permissive terms added in accord with section 7 apply to the code; keep intact all notices of the absence of any warranty

Removing notices can be very dangerous, and should not be done without legal advice. The default way to include GPL is to also have an absence of warranty, which is explicitly required to keep intact in modified version.

[nitrogen]

Removing notices can be a crime subject to a fine: http://www.law.cornell.edu/uscode/text/17/506#d