So... I actually had a dream kind of like this last night. Meiling was guarding the gate, but she was now "the youkai of the impregnable fortress," or something like that. A bunch of Touhous were trying to get into the SDM, but she wouldn't let them in. Aya tried to fly over, but Meiling made her shrink down the higher she flew so while she would be going relatively the same speed, in actuality she'd keep going slower and never actually be able to fly over it. Yuugi tried to bust down the gate, but she just hurt her hand on it. Reimu, for some reason, was able to grow bigger, but the gate and wall just grew bigger with her.
Then Sakuya showed up and told her she was really mad at Meiling for not letting in the SDM guests. Then I woke up.