not only will it hurt your channel, when it comes time to monetize, you wont be approved. I already know a few folks who been denied monetization for this reason. I think I only subbed 4 people when I first started, but it was because i truly liked their content, we both seem to have similar taste in trails and bikes and I also know 3 of them in person and I still ride with them till this day and we collaborate. I also got approved for monetization so this does not harm anything. Keep subs genuine, true and honest. subscribe to people who you truly like watching. Think about it, they are not stupid. Same with those fake paid for views. They will only kill you chances on getting monetized to 0%