You are asking STATE_MACHINE, but I will tell you my experience. Samples I have requested from Texas Instruments, Maxim, Analog Devices, MIcrochip and Allegro have been shipped to me without complication. Some of the items I requested from TI were rather expensive.
I have requested samples from Fairchild and National, and received them with some complication. Now I only ask them for items nobody else has.
The requests submitted to Atmel, Ramtron, Microsemi (two years ago, I'm trying again), Sensirion, and two others I don't remember the names of, were all ignored or denied.