Bridge burn is pretty subjective, but the market will ultimately determine a definition. If Destiny says the bridge is burned (seriously) and can provide a reason, then that is enough to resolve this market.

If Destiny blocks them, gets blocked, or if one party refuses to do content with the other, this will count.

Bridge repairs will not save this market. Resolution within 2 weeks of a clear bridge burn (e.g. Brittany Simon being blocked, or MrGirl's stream ban, etc.)

Some less-clear bridge burns, e.g. Fuentes, Vaush, Hasan, Fanatic, are determined by one party's desire to do content where the other party will not. These may take several weeks/months to resolve where unclear.

In this video, Destiny put the bridge burn with Erudite at 18%.