[Ulzgoroth]

I agree with RogerBW about it being a shame that the thing is conjoined, but I don't think sidelining Shadowing in favor of other skills is a great idea - It's not clear Stealth properly covers blending into crowds at all, and while Observation does somewhat fuzzily include not being obvious about your surveillance, the the need to keep track of a moving subject without arousing suspicion places unique demands. If you did insist on eliminating the skill, there almost certainly should be a Technique involved.