I agree there can be interference, but not all the time and it's more noticeable from the other guy's speaker than yours. Occasionally putting the headsets on after cruise, I forget to turn the speaker down (or the other guy forgets). We're lucky that we have a culture where we can just ask the other guy to turn it down and it's usually accompanied by an "oops - sorry" and we go about landing and sorting out where to go for dinner.