[He would have been fine with her trying to untie it if she thought she could do it. Really he might even prefer it as there would be less risk...but it would depend on the horse.

He reaches into his side holster and pulls out a retractable pocket knife before holding it out to her.]

You only need to flip blade out...and keep it hidden. We'll see how it reacts to us, but I'll keep its head away so it won't see if it you do have to use it.

[He then opens another pouch on his holster and pulls out a handful of potential treats—sugar cubes and pre cut apple slices. Knowing he would he encounter an assortment of animals, he had prepared for such an occasion.]

Here.