Hi @Lini172
I can only tell you what I would do, some hosts may feel differently.
I would never start an Aircover claim over knives. I would keep an eye out for them for quite some time - many of us in the Community Center have found items in the strangest places long after a booking.
As the next guests will need knives, I would buy a new set of good quality, but not extremely expensive. Try to find a brand that's consistent in its product lines, so that if one or two go missing, you can buy matching ones again.