[@Greenie] This time with boats! 

[@agentmanatee] Look forward to reading it!

[@Masterkeun] They know all of those things since they have access to all manner of histories and treatises on dragons written by maesters and other historians

[@kingkonrad] It really depends. As far as I can tell in the actual series, a potential rider's success is greatly influenced by how much valyrian blood they have. The only non-Targ riders in Westeros history however have been Velaryons and I think the current Targs would want to keep their monopoly on what basically amounts to WMDs. 

So a non-Targ and non-Velaryon might be able to ride a dragon but their chances of ever having the opportunity to do so are incredibly slim. Especially because the Targs hoard their eggs and would be unwilling to bestow them on anyone outside the family. You'd have to find another dragon egg somehow, hatch it somehow, and then tame the beast somehow. 

After manatee posts, I'll probably start working on a mini-update that doesn't include the evening festivities but will have the opening rounds of the grand melee. So all the fighters might have an opportunity to get fights in there before me and Nightwing finish up with the later phase of the melee.