#2 is less successful and incurs more costs. Trampolines are a good one because let's say you lie about a trampoline. Ok, great, we don't have to cover any trampoline related injuries. What are the chances that you would then lie and say that a broken arm occured on the steps instead and simply fail to mention the trampoline like you already did.
You, the rogue trampoline owner, aren't really the party that the insurer is worried about. Your kid's best friend's parents are. (And it's not a broken arm they're really freaked out about --- don't make a homeowners claim over a broken arm, probably; it'll cost you more in the medium term --- it's death or paralysis, both of which will put millions of dollars on the line).
1. pre-emptively dropping or refusing coverage
2. claim inspectors concluding the company has no liability for a particular incident.
It doesn't all need to be #2 (and probably should not be), but it also doesn't all need to be #1 either.