Sure, inconvenient for me. But dangerous to the many users out there who are or will be using btsync, don't know anything about .SyncIgnore, and won't bother to do a directory comparison to realize what I realized: that their Icons folders are not being synced. I fear for others, not myself.
This is my first time syncing. I had 20GB, 250K files. I compared the two directories after syncing and I noticed that my Icons directories were not being synced. It took me a while to figure it out that this is due to .SyncIgnore including Icon? by default on OS X. I assume that this is to exclude the special file Icon\r on Mac (http://superuser.com...on-os-x-desktop). This is obviously too dangerous, as Icons is a perfectly innocent and common folder name and such files/folders are skipped silently. Until the \r character can be specified in SyncIgnore, it would be best to completely leave