Shades basically shut down when theres multiple people around, which makes them pretty easy to spot if you know what to look for. Checking the ghost room with a group will show almost no activity at first, and getting evidence becomes a real pain especially emf and spirit box stuff. Interesting thing is when everyone leaves except one person the ghost goes wild throwing things and making noise like crazy.

Best way to confirm is sending people in and out of the area while watching activity levels, and dont forget the ghost wont usually hunt if youre grouped up even at low sanity. Could get nasty though if youre alone since thats when they like to show off most. Safe bet is to stick together for evidence gathering until youre really sure its a shade, then maybe split up carefully to bait some reactions.