No, you can’t ignore Amazon’s rules because you don’t use FBA. All sellers are required to adhere to Amazon’s Terms of Service at all times, regardless of their packaging and fulfillment methods.
Sellers that pack and ship their own products, and handle returns for those products, are indeed less likely to get caught if they add non-compliant inserts to their packages, compared to sellers who use Amazon’s fulfillment centers.
But self-fulfilling sellers must still weigh the risks of doing so. As above, customers or competitors could report them to Amazon, and Amazon only has to do a test buy to see the violation for itself.