Unless they are on a vacation or away for business I don’t email workouts to my clients. I also provide Skype training, so if someone is away I usually connect with them via Skype and do their workouts in this way. The problem with emailing clients workouts is that they will get into that habit and then they will keep asking you to do it on a constant basis. Unless I charge them for emailing them workouts or it was part of the deal I made with them when they were signing up for sessions, I don’t engage in this type of dealing with them.
You might be in a difficult spot, but maybe you should make it clear to them that for safety reasons (their safety) you can’t email them workouts. It’s your job to make sure they perform their workouts safely and also your job is to make sure they stick within the parameters you have set in order for them to have an effective and efficient workout (in other words you want to make sure they keep up the intensity and not wasting their time). Another way to approach this, would be by letting them know that they came to you for a reason and it’s your obligation to keep up your part of the deal.