[jgeorge]

No. Don't waste their time, energy, and money to "network" if you have no intention of taking their offer (if they even make one at all).

Arrangements "made and paid for" can be reused, it's not like they're going to waste it if you don't go.

Also if company B competes with company A /at all/ and you go out there on their dime to "learn some of the technology" and they find out you had already accepted an offer from the other company before you even went out there, you'll probably wind up with networking experience that would be better for you not to have.