BHA ross may very well take his tour operators day trip to see the Pyramids in Cairo (he hasn't said) in which case he definately will need a visa.
Anyhow, try going through passport control without a stamp and see how far you get. Why would your tour operator say you needed a stamp if you didn't, it's not as if there is anything in it for them if you did buy a visa stamp.
Which is why I said earlier
"If you intend to do a trip to Cairo, Luxor etc, then you will need one."
And you still haven't said which airport you fly to.
We've never ever bought a visa when we didn't need one, and never had a problem. It must be you.
The tour reps always sell them at an inflated price, so they do gain.