Do you think there could be a passthrough service for people to send raw transactions (made offline) via postalmail/skype/tor/twitter and then be transmitted on the network? Would be nice for countries that block internet during unrest etc.
It's technically possible.
Don't forget SMS and Phone :-)
These could be jammed easily, directly at the source.
The government force providers to cut SMS and cellphone services and sometimes landphones in time of stress.
But a Bitcoin transaction is so few bytes it is possible to send it using CB radio data link or LW radio data links, if at the other side there is some receiver able and willing to relay it to the network.