Baseless information is a dangerous thing.
Granted the chances that GPS is a scam is pretty high, tough to quantify but let's say 95%.
None the less there is very little risk from giving them a shot with a CC.  The CC dispute process is easy and your consumer rights are etched in stone by law.
A few years ago I lost a CC.  I didn't notice the missing card until about 2 weeks later.  Whoever found it went out and made two purchases totaling around $3200.  To dispute the charge I simply had to circle the charges, send back the statement, and sign and return an affidavit that the CC folks sent me.
More recently I participated in an online Ponzi scheme that left me holding about $2,300 worth of bad debt.  One letter and about 3 weeks later I had the refund in hand.
Although they were different cards, in neither case did the dispute have any noticeable effect on my relationship with the CC company.  No raised interest, no lowering of credit limit, no nothing.  I still have both cards, they have both raised my credit limit, my FICO is still around 800, and I still get inundated with new CC applications.  
So yes, ordering from GPS is a waste of time, but if you?re diligent, and you don?t mind the temporary lose of credit line, you should suffer no long-term should the inevitable happen and you not receive the laptop ordered.