If you do them a good turn they will return it to you. Most unseelie and seelie land wights cannot cross running water, especially if it flows south. The high-tide mark is the boundary between the territories of land wights and sea wights. Some wights take offence at being thanked in any form, and permanently withdraw their services out of sheer indignation. Therefore, thanking wights is taboo.
Many wights are powerless after cock-crow.
To show fear is to give them power over you, to allow them to strike. The ringing of bells is anathema to them. So is whistling, and wearing your clothes turned inside-out. She came in those ephemeral pre-dawn moments on the borders of day and night when the world swings around and odd things may easily occur. They knew her first by a clap of wings and a rush of air.