Quoted from JakeFAttie:I'm surprised there hasn't been some new physical thing to replace the knocker, like a siren or flashing strobe; anything that says "I won!" even louder than a knocker... But yeah it also seems a reflection of the times as more machines go into private collection and location play (and winning that free game) becomes less relevant.
I do like the two games I have with bells (black knight and game show). Not for free games though.