I guess I could argue that the former is actually worse. If you know spyware is installed, you can opt to remove it. If you are not aware of the existance of spyware on the system, and it happens to have spyware, you are more vulnerable.
You could of course take the risk and assume that it does not have spyware, and maybe you're right and everything is fine, but you can not _know_ that it is fine.