I worked in food service most of my adult life, and I remember when the Heimlich maneuver became required training for anyone who worked around customers. I've seen people choke on food a few times, but the rule was that if they could still cough or breathe, we weren't supposed to do the Heimlich maneuver. It worked best when the victim's airway was completely blocked. If we did it and it wasn't necessary, we could cause some serious injuries. Broken ribs were not uncommon.
I actually got to meet Dr. Heimlich when he was staying at the hotel I worked at as a dining room host. He was in town to receive a humanitarian award, which would later bear his name. I believe it was his estranged son who was behind the campaign to discredit his more recent medical research. After that story went public, the name of the humanitarian award was changed, too.