@benol
I dont think using these tools will get you banned. I have been using it on my MAIN Account ( I have only 1) and right now my follower list is 4900. Never got banned for using any of these tools.
I use flashtweet for mass follow and Huitter for mass unfollow and I use them every single day.
You account getting banned has to do with other factors:
1. Customize your Twitter account like changing the default profile pic, changing the default background image: If you have followed a lot of people without doing these, you are sure to get banned by Twitter immediately.
2. Following too many without followers: All twitter accounts get banned at the very beginning itself, thats because people get carried away and start following thousands in a day or two.
Start slow and steady: Add about 200 for the first 5 days->get about 300-400 followers->then unfollow all those not following you -> add some 500 more ->repeat other steps
By that method, no matter how many external tools you use, there is no ways Twitter is going to ban you. My account is a living proof for that
cheers!