There is a certain pre-release tidbit that has remained unexplained: One of the early videos on
this page (the sixth video from the bottom, specifically the part starting at 02:49) shows two players engaging in a Battle Tower multi battle. There is a fairly clear implication that the communication is done over Wi-Fi; the two players create communication at the Wi-Fi Club and are transported to the Battle Tower together.
Since the game's release, it has been confirmed that all five Frontier facilities have a multi battle mode, but I haven't seen it stated anywhere that it supports Wi-Fi. However, it
is known that the Battle Tower's multi battle mode no longer allows single player gameplay (the computer-controlled tag partners are absent). One would think that the multiplayer mode would be accordingly expanded, as suggested by the pre-release video, but wouldn't this have been discussed already had it been the case?
Could anyone please check if the Wi-Fi Club now supports Battle Frontier-related communication? For that matter, are regular multi battles between four players available (they weren't in Diamond and Pearl)?
On an unrelated note, has anyone noticed if the Wi-Fi Battle Tower data is shared between Diamond/Pearl and Platinum? It is hard to verify if the same server is used, but it should be sufficient to test how abundant Platinum-exclusive moves have become in the Diamond/Pearl Wi-Fi Battle Tower.