Not seen that yet, but I watched (Radar360) a pair of aircraft, 1 mode S, 1 PAw travelling together across SE England.
Or if you watched FR24, just 1 aircraft...
The PAw guy was probably doing traffic call outs for his mate.
When it gets busy in the south east it's tempting to turn off Farnborough West so the PAw doesn't get stepped on. Although I like the guys at Farnborough West, they gave me a heads up for a non-transponder that whizzed past my nose, even tho' I was only in receipt of Basic