I believe you should put your bot chars in one PC, and your main non-botted char on other PC. If you use a proxy service that's better in my opinion due to many people with the same IP, otherwise you would have only your chars on your IP. Registering is a good idea (with different addresses and acc names). On your botting chars I would avoid crowded spawns (reports), avoid bugged scripts, and mainly do your own well made scripts, like Wesker's some time ago released (http://forums.xenobot.net/showthread...l=1#post343143).
By well made scripts I mean scripts that it doesn't look too obvious you are botting, with random paths and waypoints. For example, most scripts that go to Oramond's Depot go down always in the same stair SQM. What's the chance a normal player would do that, if there are 4 possible way of going down depot? So you could do a random waypoint that could choose any of the 4 SQM. I also add a random pause simulating a bathroom go when possible, after 30-40 minutes of hunt, moving the character to a safe random spot and waiting there with everything from the bot OFF, but I don't know whether this is necessary.
The only thing I've found by now that may explain those random deletions by players who always plays safe (not erasing stamina, getting reported a lot, etc) is the paper Wesker pointed out some time ago: http://iseclab.org/papers/botdetection-article.pdf
I'm experimenting with it right now, with my main char, 3 months botting already (windbot, I don't have Xeno right now), and I gave a script to a friend, if any of us or someone who do this method gets a ban so the theory may not be perfect.