Removing a tab cause it can, is or might be used to contain OOC talk is deemed to fail.
That is, when people share an OOC talk, they do because they want it, not because there's a channel for it, or not.
If you remove the guild chat, those actions you talked about (asking for help to guildmates not being at the sorroundings, as if using an "alert" system that places a red flashing dot on each embedded walkie talkie of the guildmembers) could be done, equally, using other means. Group, for instance. Or a tell. Would not be hard to find your guildmates, maybe they're in your buddy list already, or you'd simply use /who guild_name to find those guildmates that are online. You state this in your exposition, and it's something known by everyone.
At the good side, guild tab is not broadcasted to others (group or tell aren't either) so, if they stay OOC, they're not harming anyone but, if someone, their own guildmates.
And if those guildmates find annoying to have OOC in their guild tab, then it's their task to define how the guild tab should be used for said guild, and why. Sure, those having an OOC talk could move somewhere else (then again group, tell) but if a guild does want to have an OOC clean guild tab, I guess it's only on the guild hands to achieve that.
Another story is what for that tab is used in guilds. To that, I've no answer since I've not ever been in a guild. I'm unaware of how it's used, but yes, it's the easiest path to assume it's mainly used for OOC.
I've personally nothing against OOC talk, as long as it doesn't repeatedly intrude into others play. But this doesn't have to be the case of guild chats, since they're separated from the main one.
The tabs themselves do not annoy me. That is, even if left unused, afterall there would be nothing gained if removed. You also mention they distract you from your own play. Well, if that's for the flashing you can disable its flashing in the options menu, when i game. It might be also that they distract you, because you want to check it.
In that case, I see various reasons:
a) You expect to find there something IC, but are annoyed to see only OOC. This somehow has issues with your assumption, since you've not mentioned any circumstance when the guild chat can be used in an IC fashion perfectly suitable. (Exchanging IC information with characters who are impossible to reach IC is then OOC talk)
b) The ongoing play you're involved at that moment doesn't keep you interested enough, so you switch to "let's see what's said in guildchat" with the hope of finding something better, and get annoyed at finding OOC chat as an alternative.
So, to sum up. Trying to limit the OOC talk presence in game by removing tabs that are prone to be used OOC, is not the solution. Since that would lead with where the chat is placed, and not why it is done. In other words, it would move somewhere else, the main tab in that case, and then really could affect others. It could be discouraged with warnings and all, one might think. Not worth to start such a fight.
Why having a guild chat then? Yeah, I can only think of OOC reasons, but, in the end, benefitial (if correctly handled) for the game atmosphere. Having that guild channel, surely enforces and strenghtens relationship between guild members. Yeah, they do so by OOC means and whatnot, but at least those bounds are stablished. It is then, expectable, that the guild does act as a "united" group, when in game, cause the player feels part of belonguing somewhere.
So... don't remove it.