Loudspeaker warranties and black market products

Perhaps loudspeakers represent one of the wildcard purchases on the used market regarding warranties. Some manufacturers offer transferrable warranties. Others do not. And the real wildcard in the used market are black market products. Such products often are not disclosed by the sellers in their listings. The buyers of black listed products have no warranty coverage and often encounter a refusal of service if issues should arise. So I’m curious what the A’gon community user experiences have been regarding warranties for their purchases of loudspeakers.