Hermione watches closely as Marlene writes the address. And even as Marlene speaks, she's already thinking of ways to protect them and the rest of the people involved like she did with Dumbledore's Army. Hopefully Marietta Edgecomb won't show up and warn people...

She takes the paper and nods casually. Pretending to be only mildly interested even as she plans on definitely dragging Ron and Harry over with her. "Sounds like it could be a good way of meeting others around here. Thanks, I'll ask them closer to the date."