Irrespective of what hook or injection method, known or not-yet on the detection 'radar', none are safe - it's merely that anything not yet being looked for (by whatever means) is logically safer for the time being, until it's looked for or generally it fits into an anomaly state as far as an anti-cheat system goes.
So, in simple terms - there is no such thing as a 'safe' unauthorised mod and hook/injection/link combo or any part of, just combos that are, for the time being, 'off the radar' in terms of being looked for, in a similar way to how sane mod users use 'off the radar' mod functions (things without obvious visual or disruptive effects) only and don't get picked up for using obvious anomaly code nor get reported by witnesses (at least for a short time).
But as far as GhostHook goes specifically, I can't say as i use my own experimental private 'hook' for my live code testing in SP only.
And if you've been banned twice, maybe it's time to use a new license/account and leave your current one for legit unmodded use, as it's got flags set (which you won't be able to alter) and will eventually get you on the twenty year ban a lot quicker than you think if you risk modding with a flagged twice-banned account.
The account i SP code test with, is one on a twice-banned twenty year state - so there's nothing to lose if i get flagged on that account for using mods and code-insertions and have anomalous files sitting in that particular installation.