Typically from the red sea which has restrictions on imports right now - and likely the ones you are getting are Heniochus acuminatus which are native to Eastern Africa and the Central Pacific (but NOT Hawaii).
I say it is a risk with any butterfly's and would be careful, if not don't consider putting them in.
I agree with house. Many if not all butterflys have tendencies to nip, which yes it may not do it at all for years but there still that possibility that it can and one day it just might then your stuck with trying to get a fish out of a 10 year old tank. It is the same with angels. I had a queen angel in my reef for a while then I got this certain coral and it went crazy after it. Long story short I tore my tank down and now have to set another one up. So if it has a possibilty of doing harm then I would say no, and thats for any fish. But that just mean I'm no expert