I mean, they are technically downloading it either way, just to their cache. I don't think you can really expect people to ask permission before downloading a copy of a free game that's public on the internet. Of course, they shouldn't redistribute it without permission since that would violate your copyright. But you should probably assume that anything you put on the web could be downloaded and examined.

This is a little like putting a book out on a table with a big sign saying "Please take a look!" and then being horrified when someone picks it up and skips to the last page. It may not be what you'd expect people to do (and most probably won't), but you haven't put in place any measures to prevent it or (more importantly) asked people not to. If anybody is downloading your games through the right-click menu, they can't possibly know they're not "supposed" to do that. Some developers actually include Easter eggs that can only be found this way.

For what it's worth, I wouldn't download and examine one of your games now that you've said this here, but if it's important to you then I'd put a note in the description. Even then I think you'd be counting on people simply respecting your wishes rather than having any legal power to enforce them. After all, as William O'Connell says, everyone technically has to "download" the game in order to play it in the first place.

I'm Agree With You All... And Maybe... I'm The One That Wrong Here... So I'm Sorry... Back Then Maybe I'm Not Really Deeply Think About The Problem And Just Jump To The Point... But Now... Yea... You All Right... Thanks For Telling Me The Thing That Correct Me...

Once Again... I'm Sorry...