I'm training for a long time, just to reach 40/40 in Swordfight and Infiltration. It's a hard work and demands a lot of gold. Even so, I continue being arrested even trying to steal rogue regions. And I must say... it's a hard time to reach more than 40% in training, mainly because one day you have 45%, in another training, you have 40% once again... I faced it along the 30/35% many and many times.
I would love to play my first Infiltrator, but it seems now that it's better to play with a Priest than with an Infiltrator. The class need changes, because you will need a LOT of TIME doing nothing more than training... and you can be executed in a blink. In my humble opinion, this is the worst class in the game right now. I saw great Infiltrators in the past, in the last times all I saw are ridiculous attempts from unexperencied Infiltrators just to get caught and then deported/executed.
I doubt there's a lot of players with patience enough to spend a lot of gold - and mainly a lot of time doing nothing - for a little gain. Even an adveturer can give you more fun in a good game than an Infiltrator. Useless class in these days...