I always make it a point to include the salesperson's business card in with the Test Drive voucher, no matter what the instructions say. I also make copies of the business card and Testdrive voucher. And finally, if the TD voucher tells me to expect my GC in 6-8 weeks, I go into Outlook and set a reminder for 8 weeks from the mailout day, and make sure the 800# to call is attached to it.
The reminder usually says something like, "Did I receive my Brookstone $50 GC yet?" If I have, I just delete it. If I haven't, I call the 800# I've included in it.
I didn't use to be so anal about it, but I finally got sick and tired of looking up the numbers or calling 1-800-555-1212 to get a number to a number to a number when I didn't receive my GCs on time.
BTW, Brookstone has a lot of crappy stuff for sale. I spent mine over Xmas and bought some lame noise-cancelling headphones. Good thing I didn't pay real money for them.