It sounds like you are trying to compensate for a lack of systems engineering by changing the office layout. You shouldn't be relying on serendipitously overheard conversations for coordinating things like this.
Yeah, I am inclined to agree. However, part of systems engineering is figuring out where technical conversations happen. Apache has "if it didn't happen on the mailing list, it didn't happen" as a rule precisely because they want to avoid the unreliability of serendipitously overhearing conversations, precisely because that's important to how they engineer systems. I would be a fan of a system design / an office layout where everyone has a private room and all conversations default to happening in email or group chat, and in-person conversations (which are, on occasion, definitely needed!) require some activation energy.
However, lots of in-person offices like these serendipitous conversations, and that's often pitched as an advantage of open plan layouts. That's also pitched as an advantage of getting lunch together, team outings, etc. etc. If you're going to decide to use this advantage (which I think is okay, but suboptimal), you had better put some systems engineering thought into how you want to use this advantage.
On one hand I totally agree with you. On the other hand Conways law exist for a reason.
I see no reason why this shouldn't be another case of "[...] these ought you to have done, and not to leave the other undone."