Yes, this will be true 99% of the time. Although I think that most people understand the concept of "backups" in a basic way, and backups are one of the best tools for mitigating ransomware and wipers. Especially for small businesses which are not going to be able to mount a coherent defense.

But if the relationship is important, they will be open to the conversation and it may be worthwhile. For some of us, it may also present a business opportunity.