Story spoilers - why this oversight?

Overall the story was decent, but there’s a pretty big fail in there and I don’t get how they could’ve left this in as is, or even why this happened at all.

I’m referring to the deal Lorath made with the tree of whispers, does anyone have any plausible explanation for why he did that? Sure he was in need of Liliths location, but like they did before and do after, they use the sightless eye to check on her location. So why would he make a deal when there’s absolutely no need? Felt this was very weird and sudden without any reason or logic behind it.
Guess it’s a minor issue overall, but this really bugged me.

SPOILER:::::

Because as they already saw, using the eye let’s Lilith see them right back, know what they’re doing, etc. It’s even used as a big plot point later on. When the game of I Spy works both ways, you don’t use it if you can avoid it.

True they know she can see them back, but at that point it’s just that, and their location is completely irrelevant at that time, Lilith isn’t looking for them or trying to find them, she’s heading away from them.