Yes, and even the less honest contributor would need to manually review and modify most generated blocks to pass a sniff test. The same has always been true of “found” source code.
That is, even contributors who read the policy as “don’t get caught” still have to meet the same de facto standards, which to a maintainer is a satisfactory result.
Example: I block illegal websites on my network, not because I care whether my roommates or their friends access illegal websites, but to require they practice proper hygiene (i.e., they need a VPN and encrypted DNS to circumvent) so we don’t amass love letters from our ISP.
Projects that don’t prohibit LLM-generated code expose themselves to greater liabilities than mere low-quality contributions.