No, I have never done that, but I did come cloes last week while on the San Juan river. Was fishing midges when my buddy asks "Is that you fly box floating down stream?" Sure enough, my precious (yet free to me) Wheatley was floating downstream with ALL of my 100+ hand tied midges! YIKES!! Thanks to him for spottong it and to the wheatley for floating. I quickly had it back.
If I lost a bunch of flies I would tie them, but if you do not tie then this company is pretty good. A dozen of standard patterns for around $3-$5. Granted, the flies are foreign and you should expect at least one to be notably flawed or coming apart. The other 10-11 are really nice for the money, they catch fish and aren't bad flies at all. Orivs quality? No, but you will loose VERY few fish as a result. No state tax unless you live in AZ, too.
Check them out.
Volusion Demo Store
Some patterns are more "exspensive" but still very reasonably priced.