Right now the spellcraft DC (to identify being scryed) is, in my view, very low. I suggest this DC be changed into being an opposed spellcraft check (the DC is the scryer's spellcraft).
If that isn't done, I suggest at least raising the spellcraft DC substantively.
Note: the wiki says one thing about the DC, but I don't think is the case in game. So the low DC might be a bug.