It's an issue that's needed a definite decision, and personally I'm happy enough with this proposed approach. Opt-in / Opt-out both have advantages and disadvantages, which will appeal / not appeal to each individual.
I'd recommend extending until next Monday the time to allow players to rename their secret warps, as not everyone is as active during the week.
/listwarp is essentially useless unless you've forgotten a warp you've only recently created. Happy enough to remove it, and occasionally post the current list (excluding "secret.xxx" ones) on the public forum so that people can check and clean up any old outdated ones they have.
In regards to the /tp linkage, I personally think it's usefulness outweighs other considerations, however a bit of courtesy in not /tp'ing to someone unannounced or where they aren't obviously (from in-game/voice chat) in a non-private place mitigates some objections.
Although the scythe isn't pre-eminent among the weapons of war, anyone who has been on the wrong end of, say, a peasants' revolt will know that in skilled hands it is fearsome. -- (Terry Pratchett, Mort)
Playing: Killing Floor - Other Stuff