My lot have had two that I know of. One was over Switzerland and one over France.
Neither had 121.5 selected.
Personally I use the ACARS to get any en route weather and keep 21.5 on whenever I can. Most of the time during the summer months you can just keep 21.5 selected as you don't need to get any weather - you can see for 200 miles in cavok! (Ops manual states only "relevant weather" need be recorded on the plog).
We followed Air xxxxxx (Spanish Charter outfit) up from "down south" the other week. They failed to talk to Brest and London and were intercepted by two TCAS blips over southern England. So at least we are on the ball in UK as well. I was surprised how long it took though before we heard the RAF on 21.5 . I would have thought they would have met the Air xxxxxx at the UIR boundary.
All ended fine with the Air xxxxx apologising for their finger trouble and the Brylcreme Boys peeling off home for tea and medals all round.