Nobody is likely to cancel their journey just because there's no catering. They are going to be travelling for a reason - be it a holiday, meetings or visiting friends/family - those aren't going to go away just because there's no hot dinner on the train.
But people do like to plan alternatives. If you know in advance, then you can bring or buy sandwiches.
Even a "we're not sure if we are going to be able to provide catering tonight so you might be best advised to bring something" would be worthwhile.