Originally Posted by
warthog1984
If it's just a normal taxi/bus/train... yes.
If it's a 5-page, 1000 mile, multi-day, itinerary across 3 different modes of transport... no.
+1 - If it requires either a lot of time and sophisticated knowledge or it requires the use of a "chit" / contact by the concierge, it's worthy of a tip (a significant one as others point out).
The concierge can also be really helpful with in-house issues too. If you are a regular, keeping the concierge on your team can help with room assignments, keeping you away from touring rock bands and the like.