Lambert is right, of course. Foster doesn't know about anyone else's efforts or failures in tracking because no one tells him anything, but his inability to locate what was effectively an extension of his own will back at the manor was clear enough.

It was mostly an easy spell to offer--boring, but Lambert's magical directions do skew towards boring. The thing is, Foster hates boring. He'll obey it, at least for now, if he has to, but... well, his eyes light up a little at Lambert's interest in the more experimental idea.

"Curse is only a technical term," Foster explains with a humourless smile. "But it can be... ah, inconvenient. There won't be any exceptions to it. So you might want to stick close." He laughs--it comes out less humourlessly than his smile, but it's an unflattering kind of humour.

"And magic is... a process, where I'm from. If you blow something up, that might be more memorable than the spell is worth. At least until I know."

Foster is atrocious at selling himself; often he doesn't even realise he's doing it. As far as he can tell, he's told Lambert what the spell does. What else would he want but the risks?