@tsarstepan,
1. Occasionally some of these one-post A2Kers start a thread that I want to actually post on.
2. Then I become reluctant to post on their threads because I feel that they never had any intention of posting again.
3. Sometimes I intentionally wait to see if they post more than once before I decide to reply or post on their threads.
4. I normally wait to make sure that they are not a (one and done) never again heard from, A2Ker.