i guess its as safe as stealing 1€ a day from your mom´s purse... you can never be on the "safe" side if you do something like botting. 1 report from a guy may be enough ...
bans right now are only from reports - or abuse of economy if you move gold - or of course, if the banwave will come
nobody knows. Blizz has bein doing one about every 6 month for the past 18 months - and yes if blizz detects the bot in a ban wave and you have been using HB during the detection window(s) you will get a 6 month suspension
well there has been one in december 2015 and one in may 2016 - if there will be a banwave this november/december or even earlier - who knows