If people can be safely stowed away in a Bag of Holding™ like that, then what's stopping him from just effectively smuggling her into the city? Do they have some sort of bag scanning magic at the gates? But hey, turns out he and any of his companions are exempted from any and all gate checks anyway thanks to Ziegline...
As expected, Ziegline was jealous of Kaya. And boy, her jealousy is a sight to behold. The situation only got salvaged after Weiss explained that she's some self-proclaimed expert tagging along to help with materials (and certainly not his latest woman). Ziegline, probably not wanting to believe her beloved Weiss is really a womanizing playboy, relented.
If we take a step back, it looks like the two of them effectively let some country hick freeload off of them. Not sure about her becoming a regular part of the cast, that seemed way too easy. Either Weiss or Ziegline needs to draw the line with pushy girls like this or they'll find themselves building a harem soon. Girl's totally pushing her luck here.
In any case, I'm just disappointed some random new girlie got into their lives so easily, while Holo got left behind trying to make a living in crappy ol' Zenith...