What if they could be got to go back suddenly to their homes, and bring a legion of red-haired Gauls to assist the conspirators in burning down Rome?
A deputation from the delegates came to Sempronia's house and there met the conspirators--Lentulus and others.

They entered freely into the project; but having, as was usual with foreign embassies at Rome, a patron or peculiar friend of their own among the aristocracy, one Fabius Sanga by name, they thought it well to consult him.[203] Sanga, as a matter of course, told everything to our astute Consul.
Then the matter was arranged with more than all the craft of a modern inspector of police.

The Allobroges were instructed to lend themselves to the device, stipulating, however, that they should have a written signed authority which they could show to their rulers at home.

The written signed documents were given to them.

With certain conspirators to help them out of the city they were sent upon their way.