I have no proof that this event happened (except for DM Defiler's post after the first event
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A Thayan merchant came to Shadowdale to sell magic items. Many, many people came and traded with that merchant.
The trader was seen the day after at the crossroads east of Shadowdale. Many people came as well, however this time some of them raised the issue that Thayans are slavers and necromancers, and that buying from them meant financing these evil actions. Those who spoke against buying from the Thayans were not well-received, and trading went on unhindered.