I used to get insurance when traveling but don't anymore. And if I remember correctly, insurance conditions stated what they cover not what they don't cover.
One of the most important notes (since I was a student then) was that even "the listed insurance covered situations are not approved for insurance if a person was intoxicated in any way or was actively involved in any illegal activity" (freely translated from Croatian).
I really doubt any insurance company has different policies that the one mentioned as an example. But if you know what exactly you are going to be doing during your travels, you can ask for additional insurance and will almost always get one no matter how obscure you think that activity might be but be prepared to pay a hefty sum depending on what you propose to them since they will sometimes create an additional coverage especially for you... Or they'll just tell you that they won't cover that in any way if it's too risky.