You could start to build a modular kit for yourself and then show it to the people you want to carry a kit. Ideally the modules should have a size between an Altoids tin and two packs of cigarettes.
Then you could start by making up realistic scenarios and let them solve them. I would start with less serious events like loosing orientation or a sprained ankle.
One reason for not carrying a kit is the prejudice that it it takes too much space and weight. That can be overcome with examples. The modular design allows to use the infamous "Salami tactics" for sneaking in the entire kit.