There are always people being banned, but as I understand it, there is a trend that more botters report bans after major patches.
When you say safe to use, I'm not sure what you're getting at. If you're asking whether more bans indicate that the software is detected, well no, as blizzard would ban everyone.
If you're asking if you are more likely to be caught botting currently, then that answer would depend on what you're doing, as there tend to be trends where certain activities are riskier at times depending on what activities blizzard is trying to track.
In my experience it's the people running multiple accounts, botting in an unsafe manner, and farming gold to sell that tend to be banned. As someone who bots on 1-2 accounts for fun I haven't been banned since Wotlk. Anecdotal of course, but the ban reports forum shows the very small minority of people who have been banned in the overall absolutely massive honorbuddy community.
