An exclusion is a maintenance instruction written years before the claim. Five things to check in the form your insurer filed, and what each one asks you to do now.
Exclusions read like a list of ways to be turned down. Most of them exist because the risk they name behaves in a way ordinary insurance cannot absorb.
A big customer's contract is written to protect the big customer, which is normal. Most of it is negotiable, and knowing which parts to push on is the whole skill.
The protection is real, considerably narrower than most owners assume, and easier to lose than anybody expects. The rest of the decision is bookkeeping and habits.