when buying shards it should be the player who chooses not to buy from the obvious bot user who has 10-20 entries of 1k shards on all the types of shards.

its so obvious which players are not doing legit mining/lobotany to sell shards yes a player can gather a few thousand shards to sell but its unlikely even the most dedicated gatherer will have 25,000 shards up for sale all the time.