That's a bit worrying, what was the goofy suggestion ?
I cannot recall the exact procedure, but it had to do with applying my own glue and then sticking that to the head tube and down tube. This, alone suggested to me that he was aware of the issue. I almost forgot, in his instructions for use, included with my purchase. In addition to using a spoon to smooth down the decals, and perhaps a hair dryer to help them stick. If that failed, then I was to get some kind of white spirit based varnish, and ensure that I did not use cellulose to seal the decal...
Honest to goodness, these were the written instructions! I just said to heck with it. And the bike sits, unfinished and off of the radar, probably for quite a while.
Again, the decal seller tried hard to help me out, with guidance and the offer to return my money. None the less, the ball was dropped. If he has supplier issues, then he needs to deal with that. If he has application concerns, he needs to mention them before the customer purchases.
Again, just an old fellow's opinion