I've been watching 'Ghost Whisperer' for a while now, "yeah I watch really bad American TV, so what?!".
But, Melinda tells at least 2-3 people every episode about her "ability". Seeing how people gossip, surely now that we're in the 5th series most of the town know about her ability. People gossip loads, especially in small towns. Everyone should know about it, and she runs a small shop in town, there should be loads of finger pointing and hushed whispers but apparently not. People still seem genuinely surprised when she tells them. Even though, she spends hours talking to herself in the main square, in plain view of everyone.
Or is there a small clause with her helping them, that they then have to leave the town and never mention it to anyone ever again?
Or is it like 'Murder She Wrote', where they all know she's the kiss of death, but still feel a desire to be her friend!