The 1/2 troop/resource punishment is a setback, to be sure, I do not deny that. But, by no means does it truly impede a botter. Half of a crap-ton of troops/resources, is still a horde of troops/resources. Instead of 50x my troop levels, they only have 25x my troop levels. In less than a week, the bots recover the losses while the player watches TV. I have no problem with the suspension punishment being only 1/2 of the troops/resources, since that is easily recoverable for an innocent that may get accidently caught in a sweep. But, please don't pretend it is a crippling blow, by any means
The policy of...
First offense: 3 days suspension
Second offense: 7 days suspension
Third offense: permaban
... is NOT being adhered to.
I have heard of player on their sixth "3-day suspension" for botting. I will admit I have heard of quite a few repeat offenders being escalated to the 7-day suspension. Then they simply repeat the 7-day version of the punishment a half dozen times. But, I have only ever seen a handful of repeat offenders ever escalated to the permaban level of punishment. I could count the permabans I have seen on my fingers. I would not need to take off my shoes to use my toes to count the permabans I have seen.
As for your gauntlet...
I don't come across many bots, because I don't fight very much. I find little area to set up a single city. I join whatever alliance has control of that area, and I keep my little corner of the world tidy. I don't venture much farther than 20-30 miles from my coords. I play the 1-city playstyle because I don't have the time or energy to compete on par with the massive amount of cheaters that bot/multi/share. If Evony was a place where I did not have to fear uncapturable foes with armies 30-50 times larger than me, then I might get brave enough to expand again.
If you want information on bots, check the helpspot tickets. There are thousands of reports on botting players you can take your pick from.
I also do not know what bot programs are available, because I have never sought out those sites. In fact, I make every effort to avoid even accidently going to those sites. I am concerned I might get a cache file, or temporary cookie that may tag me as a botter to your sentry software.
Instead of sweeps, may I recommend...
I do know someone in another alliance was working on an anti-bot script. Once he found a botter using a defense bot, he would send the script. I was told that he successfully knocked the bot off slightly more than half of the time. It would be awesome if Evony could utilize this tactic. Go to those bot sites, and look at the software. Maybe the devs could find the commands that turn each bot "off" and add those scripts to the 6 minute "tic" of Evony. So many things happen on the tic already. If 90% of the bots got knocked offline every 6 minutes, they would become very difficult to use, and players would have a good chance at beating them.

