available guild trader booths?

scipionumatia

The other day in my hunt for sharpened ravager weapons I visited every guild trader in the game (xbox NA). while at some places (bleak rock isle, khenarthis roost) I saw there were what looked like vacant guild trader booths. is that what happens when no one bids on a trader? on that note sometimes the middle trader on the anvil docks is MIA week to week, prior to seeing bleak rock vacant booths I assumed she was glitched and not loading in.
Anyone know?