Operating BI098 LHR-DXB about one month ago, FL330 over Frankfurt. F/O nearly jumped out of his seat as a met balloon passed just off our right wingtip. I was saved, by page 3, "car in ditch"story,the Borneo Beano, from witnessing anything!
ATC seemed fairly disinterested.
I suppose it is part and parcel of the risky nature of our job but it would be an unfair way to go!
Many years back. when real men wore white hats, it was me receiving the shock, from the righthand seat, B757,climbing through FL290 over south coast of UK as we passed through a cloud of party balloons!
Makes you blink!