Seriously, some people might do well to mind their own business. It's none of hers what you are or aren't buying and why. It's not like you were beating a child with a cane to take the pony out of her hands.
I can understand why some collectors might feel guilt over buying 2nd hand ponies for the reasons discussed, but we can't live our lives thinking "what if" for everything. Sure, if you left the pony a child might have bought it, but it might just as likely have gone to someone who would've immediately put it up on ebay to make a quick buck.
Elf