I think this takes us back to the point about whether the idea of the whole plane being decontaminated for one person really makes any sense.

Surely it would make far more sense to have some kind of allergy-safe meal package (appropriate for class - this isn’t about being discriminatory or forcing a cold sandwich onto a CW allergy sufferer) which was sealed, heated with the foil seal still on, etc. etc. so no risk of crumb contamination in galley until opened at seat. This may sound involved but at least you are then taking special measures for the affected person, rather than trying to manage hundreds of orhers

i’m afraid I simply don’t believe that someone opening a packet of nuts 5 seats away makes the slightest difference. Contamination of the actual sufferer’s food is the real risk and this can surely be managed with some proper precautions including dedicated (pre-ordered) food packs, policies and training, rather than voodoo “we will not be selling ...” announcements.