You could tell them to either confirm again by a certain time or tell them you don't take advance bookings and they can call when they're in the area?

I get them to confirm.So if they book the day before for a morning/early afternoon appointment then I ask them to text me to confirm between 8am and 10am.If it's same day but they have booked for a late afternoon/early evening appointment then I get them to confirm an hour before or when they tell me they would be setting off to get to me.

Similar.
Except for short notice bookings, they all must confirm 1hour- 30 min before. Regardless BR or not. If they don't, I just assume they cancel.

Rather than double book, I say to the person asking about the unavailable appointment "I'm booked then but I haven't seen this person before, would you like me to contact you if they cancel or don't show?"

Sometimes they say no, sometimes they say yes but have sorted someone else by the time I invite them to book but  a lot of them tend to be in the area and able to get to me within 10-15mins or so.

I try to be honest with clients wherever possible, I've been on the receiving end of his kind of thing at a beauticians and it infuriated me.  You're not going to end up with any less clients by being straightforward with them.

In all likelihood double booking will lead to negative feedback somewhere.

Sorry, should have mentioned that I do use a confirmation system ... I ask all to confirm 1hr before and in this case they all did. x

I feel for you. I get some days when i get no shows and cancellations all in one day. Now i only take advance bookings the day before which has improved the system somewhat. I Get them to confirm the morning before 10 am as most of enquiries seem to come in after this time and get them to text me when they are on the way. I don't double book a client who is booked via AW as i don't want bad feedback but would double book callers and go for the first one that shows or if a good regular calls up i see him and cancel the newbie

Sorry, should have mentioned that I do use a confirmation system ... I ask all to confirm 1hr before and in this case they all did. x

Maybe accepting short notice bookings only will help.

I just tell the guys it's a first come first served but once we have met once they can book. Asking them to text on way helps too.

 Xx