if you get a flight North America-Switzerland-Italy to Italy-Switzerland-North American and only fly North American to Switzerland on the way in.. will i still have a valid Italy-Switzerland-North America ticket awaiting my return home at the end of my holiday?

i don't require a visa for any of the stops on my itinerary.

In a word, NO.

If you miss any flight in an itinerary, all the rest of the flights will be cancelled.

If you buy two separate one way tickets, you can do what you propose, but outbound and return must be separate tickets.

Sure, if you contact the booking agent/airline and pay the change fee and/or fare difference your ticket's requirements put forward.

how is that legal?

I cant find a swiss fare within 20% of my 2 stop italy fare.. Yet the 2 stop italy fare starts with a direct flight into ch.

Then i need to be in italy for the last leg of my journey anyhow.. would save time and money.

Supply & demand compounded by ticket requirements.

You want/need to be in certain place at particular dates and want the airline to enter into contract for those details. They will charge you such an amount for that contract with such rules. You break the rules the contract is broken.

You could book a RT USA-Switzerland and independent travel to and from Italy but you do so at your own risk of missing the return flight to the USA unless you give a large amount of time for problems. For me in such instances it's 1 day.

It not illegal. Governments do make the rules or pricing for commercial flights- its business
The distance you fly and the airports you fly into and out of have nothing to do with the price of the ticket.
Supply and demand and market share at work.

Only 20% difference is good. It can be 200%
Look for another route and/or Eu trains

You should search for 'hidden city ticketing' here. It is extensively discussed.

Thanks for all the replies.

Hardly seems fair. I'll look into alternatives

Check US-Swiss and flying our Milan-US as this will likely reduce the fare difference by half or more. Train Swiss-ITA

The other risk of getting a USA-Switzerland-Italy ticket, planning to get off the plane in Switzerland, is that the airline doesn't promise to take you to Switzerland unless it's specifically listed as a stop-over. It promises to get you to Italy somehow. If anything goes wrong with its schedule, weather, mechanical, involuntary bump or anything else, they may find it easiest to get you to Italy via (say) London or even a non-stop from a US gateway. If that happens, there isn't a thing you can do about it other than staying where you are, assuming your citizenship and entry status permit this.

This is called hidden-city ticketing and it's maybe the subject of the most questions on FT. You are asking, of course, because you see it's cheaper to fly to Italy than to Switzerland. Leaving aside the morality of trying to fly to Switzerland for the price of the Italy ticket (which has been debated here ad nauseam -- let's not start that up again), the fact remains that the airlines are on to you. They will penalize you for abandoning the second leg of your outbound trip by cancelling your homebound trip.

People sometimes get away with this if they're only flying one way, check no bags, and keep their frequent flyer number out of the mix. But it's not recommended regular practice, and never in your (round-trip) case.

As several others have noted, your return flight will be cancelled if you don't fly from Switzerland to Italy. But there is also another problem. When you land in Switzerland, you'll go through immigration and have your passport stamped, but any checked luggage you may have will go straight through to your destination in Italy.

If it's the quoted price, fairness doesn't really come into it.

Not sure what you mean by "fair". You can absolutely do what you want to do. Either purchase two one-way tickets or make changes to what you propose to purchase now. Each different option represents an agreement between you and your chosen air carrier.

Only you know whether the ticket price for the itinerary you want is a price you are willing to pay. If it is, you should purchase that ticket. If not, you should not.

Germany, by way of example, requires air carriers to make available tickets which have the feature you want. However, those tickets are much more expensive than those which are ordinarily purchased.