Currently checkuser's-massblock interface instructions says:
"Selected accounts will be blocked indefinitely, with autoblocking enabled and account creation disabled. IP addresses will be blocked for 1 week for IP users only and with account creation disabled."
I've noted that CheckUser mass-block interface currently disallows talk page editing too, but that is only noted on [[Special:IPBlockList]] and not on [[Special:Log/block]].
Example - blocked with the extension:
- Block log: http://meta.wikimedia.org/w/index.php?title=Special:Log&type=block&page=User%3AAnanev
- IPBlockList: http://meta.wikimedia.org/w/index.php?title=Special%3ABlockList&ip=Ananev
This seems not to be an expected behaviour.
Ideally the extension could be updated to have checkboxes to allow blocking email and talk page.