Our farrier has "friendly reminders" (aka rules lol) spelled out on our receipts and one of them specifically says:
"Please have your horse(s) ready: haltered, in stall or tied, before your scheduled appt. time to ensure quick service and so I can maintain my next appt. time"
Even has one on there regarding mare/foal and asking that the foal be restrained while he's trimming the mare, said we wouldn't believe how many places he's gone to trim mares (both mini and large) and they'd allow the foal to roam around while he's trimming the mare, of course when the foal went out of sight the mare(s) would act up and get fidgety or the little snot would come up and nip him while he was bent over
Also asks that if the scheduled time is around your typical feeding time, that you feed your horse early, we all know how cranky a horse can get when they know it's feeding time! To me it's kind of sad that he has to spell out all of these things when it should be pretty much common sense!
He schedules a set time and is typically right on time, or on the early side, don't recall him ever being 'late', so I have no problem about having our horses caught, haltered, tied or in stalls, depending on who is being done.. I would never expect him to go out and catch our horses, while our horses are friendly and easy to catch, what would happen if he were to get hurt or vice versa, one of the horses, since neither knows each other?
The last time he was out we had 2 mares, 3 yearlings and 2 foals clipped, all were caught, haltered and tied (with exception of the foals) in anticipation for his arrival.. We always have two people available (typically myself and then one of my siblings or parents) to help him, he'll clip the first and as he's working on the last hoof the other person will have the next untied and waiting so when he's done with the one horse we can move the next right in, that way he doesn't spend any more time here than he needs too and can make it to his next appointment on time.
One of the farriers we used when we first got our trail horses, ended up getting kicked by a horse he was trimming alone, no owner was there and ended up having severe back injuries, he's no longer able to do farrier work