It might well be about resources - if you look at the LD national campaign it's, yes about showing off Vaizey, but it's also about policy and 'broad thrust'. The national party is doing the national campaign, and the local constituency campaign is down to whatever resources the local party has. If that's 'not much', then this might be all they've got.
It does seem a bit odd, I grant you - though I suppose it does stand out from 'random person in suit looking unhappy in front of closed toilets' or whatever, so it might have more impact, even if there's not much on the (local) policy front.
I've got no idea if Sutton Coldfield is a genuine target seat for the LD's, or whether this is just going through the motions...
E2A: LD's are nowhere in Sutton Coldfield - straight Tory/Lab fight. LD's predicted to get about 6%, down from 12%.