Where I'm at, we allow singles to book tee times. We even have times where a tee time can just have one person. If there were to be a uniform policy for all courses regarding singles, I would say if you know you'll be a single, just call the clubhouse and see what's available. I've done that with courses in Coralville, IA and Iowa City, IA and feel it works quite well. The only thing I would want to change is booking for a foursome as a single, and knowing you'll be a single. Theres no reason for it.