Amadeu Moles hears about the Convention at the same time as most of the rest of his friends among the business community of Rikkan Ports. The reactions are varied, of course. Several of his friends immediately and sensibly conclude that getting anywhere near a Queen is a bad idea and liable to get you killed. But Amadeu inquires further. 

There are going to be a thousand delegates. A thousand is a lot of people. Even a Queen can't murder that many people at once--or, she can, but she'd have to actively plan to murder a thousand people, you can't murder that many people for coming to your notice because you can't notice that many people, not all at once. 

Amadeu Moles investigates the purpose of the Convention further. It's still mostly opaque to him, but he gathers that one of the new Queen's Archmage-allies is from Galt, and wants to do a weird Galtan thing, and the Queen is humoring him about it. 

Obviously there's no reason for the Queen to let the Convention actually inconvenience her, but maybe, if it produces some good ideas, those ideas will be promoted to the attention of important people. 

Also a lot of nobles are required to attend, so it could be a great networking opportunity. 

Amadeu bribes a servant--not a slave, a free servant, there are some tasks you just can't trust a slave with--to allow himself to be bribed by one of his enemies to let slip when he's going to be out of town, acquiring more slaves to sell on the river ports, so that the enemy can assemble the community while he's gone and volunteer him to be elected to the convention by people who did less research because they had already written it off as a death trap.