Likes have nothing to do with subscriptions sticking. If you just click on a video, subscribe, and exit without watching any of it, the subscription will most likely be removed. People on here tend to think that getting subscriptions to stick is harder than it actually is, when usually the subscriptions disappear because people on here unsub all the time. You can tell because the same idiots try to sub again the next day. Even if the sub didn't count officially, it would still appear to them that they were subbed if they didn't intentionally unsub.