I don't think I've ever heard anyone complaining that a collector used their scans for personal use in their binders or to show an example of what we're looking for.

What we have seen in the past is several things:
People on Ebay stealing a scan and using it - when the actual product may (or may not) have been inferior.

OR people who use the long hours and hard work of others as short-cuts to selling their own items quickly and painlessly.

I know I have spent so much time with Paul Hegge on scans and exchanging data for the Nevada ChipGuide, I was beginning to feel like we were married.
I don't care if people use my scans (for any reason as long as it isn't illegal or unethical) - but someone like Pete Rizzo that has... LORD!! THOUSANDS of scans on his site... for sale... for show... it seems a little unfair for someone like me to waltz up... borrow his scans and sell everything he has for a buck or two less, using his examples.

I'm sure there are other reasons... but if you cut a pic for your binder... no one cares.
Some people just appreciate your asking first... or mentioning "scan courtesy of Greg Susong's ChipGuide" or "Archie Black".

EVERYONE steals Greg's and Paul's scans! It's am "implied" perk of the hobby!
But we shouldn't borrow them for convenince if selling... I feel we should always scan what we're selling or trading so folks can trust the ole "what you see is what you get" philosophy.