"Last changed" timestamp is ignored?

[Carey O'Shea]

Rsync's "does this file need to be updated" check can conclude "this 
file does not need updating" even though the "last changed" timestamp 
differs. This happens when the size and modify timestamp are equal. Why 
doesn't rsync consider the "last changed" timestamp in the same respect 
as the modify timestamp? Doesn't changed mean, er, changed?

I noticed this when editing some Ogg Vorbis tags with a tag editing 
program (Easytag). The size and modify timestamp remained the same, with 
only the "last changed" timestamp being different. The updates were not 
transferred because rsync saw that the size and modify time were the 
same, and concluded the file did not need updating, despite the "last 
changed" timestamp being different.

I see no reason to have to make my transfers take multitudes longer with 
--checksum or --ignore-times when simply checking the "last changed" 
timestamp in the same manner as the modify timestamp would be trivial as 
far as I know.

Perhaps there is already support for this and I'm just not aware of the 
option? If so, then why isn't it the default?

I'm using rsync 2.6.9.