Yeah, it’s annoying and if I’m being honest, it makes you look like a douche IMO. The fact that someone would follow you, only to unfollow you in the hopes that you follow them to boost their follower:following ratio makes you look douche, and just further feeds people’s narcissistic tendencies.That same thing happens to me everyday.
At first I thought it was instagram removing my followers because I follow very few people, but then I've read an article on a blog about this follower-catch "technique".
I've put a disclaimer on my profile saying that I don't follow for follow, but every day I got a bunch of stupid morons following me just to unfollow on the next day, or hours.
If you want to follow me because you like my images, cool, but don’t expect me to follow back. I only follow people that i want, mostly friends/family, some forum members here, and Motorsport photographers.