I recently purchased 2 packs of Verbatim White Inkjet Printable BD-R TL 100GB Media (20 disks). Of those disks, three were coasters. Needless to say, I was not happy. These disks are expensive. Toast Titanium failed with:

The drive reported an error, Sense Key = HARDWARE ERROR, Sense Code= 0x44, INTERNAL TARGET FAILURE

So I reached out to their customer support, and after verifying my receipt they sent me a new 10-pack free of charge. Even though I am still disappointed that 3 disks failed to write, this more than makes up for it. Great support I think.