Psi-shielded shouldn't be a problem as only the heroes would have that anyway, and it seems that all the heroes in attendance already know her secret identity. As for phones, yes, Emma's powers won't work on them, but all she has to do is bring someone with her who can erase data from tech. Kate's phasing power would work (walking through electronics acts like an EMP) but it's probably too slow. Maybe someone like Trinary (the new girl from the first X-Men Red series) could do it, she's a technopath.