This doesn't really answer your question, because I don't know if there's a performance hit or not, but why even bother including the "using..." for the OleDbClient if you're not going to use it?
Okay. Poor Example. I'll try to explain...
If you're familiar with Mere Mortals for Fox you'll know that it has a program full of utility functions. The current version of Mere Mortals for .NET doesn't have this particular utility I need so I'm thinking of creating it for me to use.
I was discussing the fact with Jason whether this utility file should be included in a namespace that other heavily used classes exist or should they go into their own namespace. Granted, most of the time they would be used by classes in one namespace but a lot of times they wouldn't even be glanced at. Then we got into the discussion of performance. The only reason we would care is because of performance. If the performance doesn't matter then the namespace doesn't matter since they'll be used by a set of classes anyways.
Design takes a lot of fore thought and we didn't want to get cornered including these namespace where they're not needed or vise-a-versa.
But for the most part I agree with you... I wouldn't include the namespace if it wasn't needed.
