Instagram has added a new feature in their current release called Post notifications that allows you to get notified the moment someone posts a new photo. You can think of this much like following someone with an added bonus. Instead of them just appearing in your regular feed (or you having to manually visit their profile) you instantly know when a new picture was uploaded.
To access this new feature you go to the persons profile you are wanting to be notified about. Click the three dots in the upper right corner and the above menu will appear. From there simply turn on post notifications. You will then get a separate prompt from mentions of your name, and comments or likes on your pictures letting you know they have a new photo to view. Of course normal block and privacy rules apply.
So does this really mean more stalking? It does remove the need for someone to constantly refresh your page or profile. Mainly if you are public. Understandably a person would block someone they did not want following them. But how do you know someone is not trying to suddenly show up at places you are. It is all about posting smart and controlling what and when you share something.