Yes, you can do it. You can make multiple posts in the ad sections on the same day too. Can is the operative word - as in it is possible. But doing either will violate the rules and the post/s will be removed and you will suffer the consequences that are deemed warranted. As to how I would enforce it - that's easy, the mods carefully review the ad sections every single day. And yes, all of them.
I do and I did. And just because some specific scenario isn't spelled out in the rules as being against the rules - that doesn't mean it isn't against the rules. It would require an entire book for the rules to cover every possibility that exist. The rules governing the ad sections are simple, and straightforward. They dictate who may post there, when they post there, what they may post there, and the one and only way you may respond to ads. That's all they need to cover because everything else is against the rules.
Wait... you wrote the rules?! Who would’ve guessed. It’s not like you point it out every single time discussions on rules come up or anything. Anyway, seems like we’ve cleared up my questions. I guess it is up to you To decide if tagging someone in a listing is intended as responding to another listing or not. I would personally recommend specifically stating no tagging people in WTT/WTB/WTS to avoid uncertainty, but it seems you’re not interested in any additions to rules that you didn’t come up with yourself. Thanks for the feedback; I have no further questions.