this would be invalidated by:
- breaking upwards of the channel on high volume
- going sideways out of the channel
I think breaking down of the channel would still be fine but in that case I'd probably look for either a sharp reverse at the lowest support or lasting sideways.
Anyways, the idea bases on xtzxbt trending down in the channel until it reaches roughly a 70% decline from the top. I'd expect it to be invalidated fairly quickly but hey if it works I won't complain.