Would be highly convenient, but I can see why they haven't done it yet considering...
[quote name='CipherWeston' timestamp='1367177495' post='310675']
According to Bulbapedia, nowhere on the [url="http://bulbapedia.bulbagarden.net/wiki/Vs_Seeker"]VS Seeker[/url] topic does it say it's limited to routes only.
[/quote]
Actually it does.
"[color=#000000][font=sans-serif][size=3]The Vs. Seeker is also unable to be used in buildings or caves, even where previously battled Trainers are present."[/size][/font][/color]