I've been working on a 'collada viewer', and run into some issues with the blender export of animation (I think... it could always be the FCollada framework, but that's used in Maya and Max ex/importers so...).
The main problem is that the keys aren't in increasing time order. That may be due to creating keys out of order (something like start with just a cube, set key at start, set key at end, set key in middle, something like that...). I haven't done that particular sample, but have done more complex stuff where I have jumped around the timeline, and gotten odd key ordering. I'm also not a Blender guy, so I'm just learning -- for instance, I don't know if there's a way to 'update' a key, I just effective add a new key over the old key to update. But, looks like doing that, jumping around the timeline to edit, the keys get out of order (I can't send you the resulting animations, unfortunately proprietary data, but you should be able to reproduce in <5 mins...).
That of course leads to the two side effects of the first key not guaranteed to be 0, and the last key not guaranteed to be [maxtime].
Is this a bug in the exporter? The spec doesn't make clear whether the keys are 'expected' to be in some sorted order, so obviously it COULD be out of order -- but looks like at the least, FCollada isn't sorting them for me.
I'm also posting similar Q on the FCollada forum.
-d