You go on and spend that extra hundreds of dollars. I'll laugh all the way to the bank.

The Saturday night stay rule is highway robbery and air passengers are the only consumers who takes such rule sitting down.

AC*SE, you said, "If back to back tickets are against the airline's tariff, then it is illegal." TRUE, HOWEVER there is a difference between LEGAL nested tickets (which do not violate the tariff) and "back to back" tickets. I think you are confusing them. Basically, "back to back" tickets are from city A to city B and back. The two tickets are stripped and used to beat the saturday night stay. Nested tickets would look like this. Start in city A fly to B (THEN PRIOR TO RETURNING to A) fly to city C. Return to B. THEN, and only then, return to A. The key is you did not return home (to A) until the other flights were taken. All segments paid for were flown on the original days. None discarded, changed, or altered... NO violation. Hope this helps.

I've booked nested tickets several times using CO's website, they didnt seem to mind it at all.

Carefull examination of the airline tarriff will reveal that "Back to back" "Hidden city" and such are only prohibited if they result in a lower fare.