Yes, it really depends at what time you play. If you play after 23 or 24pm you could have between a 50 or 80% chances of playing with/against a bot but mainly because at that time there are not many people playing so if you face a bot and after that match you queue again, you will match with him again.
I am a returning player and i saw people complaining about bots and my first reaction were "they are just bad and people is so paranoid" but nope, there are a few guys botting pretty much everyday. Ive even see one guy with 3 accounts at the same time and he forgot to turn off the bot in the morning and he was still queuing "at a riskier time". Most of the bots are mesmers (mirrage spec) and a few of them are necros (minion master build).
Tonight i saw a bot who was using the "target call" key just to look like less than a bot, it was kinda cute lol
Sadly Anet doesnt seem to be doing something because ive seen the guy with 3 accounts for 2 or 3 weeks in a row but it is true that this week i just see him with only one account, but i would be really weird that he got a ban in 2 of his account but not in the 3rd one when he was using them at the same time.
Note: I know it is the same guy with different accounts because the account name it was the same but different number on 2 of them, and in the 3rd one his character name was almost the same as the one in other account