You don't have to choose one or the other - you could say "please open a GitHub PR if you have an account, otherwise feel free to send an patch to patches@examp

You don't have to choose one or the other - you could say "please open a GitHub PR if you have an account, otherwise feel free to send an patch to patches@example.com". It might feel a little messy to 'mix and match' PRs and patches like this, but in practice, as long as everyone uses good commit messages I have found it to be inconsequential.