What behaviour causes the robot check?
For the first time (I'm Lv33) I had a robot check from Niantic, not something I've had before. I'd just taken down three reasonably close L4 gyms in quick succession (didn't take long as one started with Rapidash and was topped with Arcanine and two Gyarados in between, the third was low CP Cloyster, Kinglers etc.). I took all three down in under 20 minutes including a quick jog between them (well quick for an unfit 45yr old), but these are gyms I regularly take control of and have never had any checks before.
Answers
Week ago I had my one and only check. As soon as I turned on the game. Did nothing that would seem abnormal. Maybe have spotty GPS, but it has never caused problems before.
Also I clicked the wrong picture and immediately realized it. I'm sure I'll get another one soon.
Maybe doing random checks now?
I get them quite often when I'm sitting at home not moving. I leave the game up all the time because mon tend to spawn in my house about every 30 minutes. So far, I've found that closing/restarting the app every 45 minutes or so seems to stop it.
But I have also found that not responding quickly enough can result in a soft ban of about an hour. Happened for the 2nd time this morning when I checked the app and then fell back asleep. Awoke to the captcha message, responded, and saw nothing for almost an hour. No mon on nearby, and the 2 stops visible from my house were not there.
Editorial aside: I find these incredibly infuriating. I get it that Niantic wants to stop bots. But they're catching legitimate players in the process and seem to be trying to ensure the game is as unplayable as possible. /end rant.
I got the sushi one too once. I get those robot things most often when I fall asleep with the game on waiting for a spawn. Try waking up to it and having to look at tiny pictures on an iPhone 5. I think I get it wrong often cuz it'll give me another one that I still can't see! But I've never been soft banned for it.
I do get soft banned battling gyms tho due to that gps drift. Which is the worst when you've just leveled it up and someone snipes you while you're banned!!!
I've had a couple for no apparent reason - I just wish they'd make the Capcha's easier - sometimes almost impossible to tell what they want ("which of the shops sell coffee - click all that apply") - easy to miss one with less than perfect eyesight and a small screen (no way to zooom), and I don't want to get banned!