[mynameisvlad]

> (something many Mac users will never even have done before)

This isn't the 90s. Two-button mice are the default now, and have been for many years. I'm pretty sure everybody has done it at least once, and probably even knows what the term "right-click" means.

> ignoring the fact that they're doing something it's telling them not to do.

They're not doing something it's telling them not to do. Have you even looked at the dialog? Have you read it yourself? It simply asks the user if they're sure they want to open it as it's from an unidentified developer: https://support.apple.com/library/content/dam/edam/applecare... Nothing in it is telling them they shouldn't or can't open the app, they're not going against anything by saying "Open" (in fact, that might just be why there's an Open button there in the first place, because it's an acceptable choice).

Seriously, you're being overly untrustworthy about your users here. You seriously can't think this is that big of a problem. Because it isn't. Other apps have managed to solve this with download instructions, it's really not difficult, and the fact that they're still alive and running shows that users clearly know what they're doing enough to right click once and press Open once. It's not a difficult task by any means of the imagination.

[derefr]

The dialog that comes up from the context menu looks like that. The one they'll see the first time they try it, though, will look like this: http://www.maclife.com/files/u12635/gatekeeper_1.png

That looks like a "telling them not to" dialog if I ever saw one.

[mynameisvlad]

If they're following the developer's instructions, then presumably they wouldn't even see that screen. Remember, we're talking about the steps needed to open the app, not what would happen if they tried to open the app normally.

I mean, that said, most instincts would be to double click the app right away, ignoring any instructions, but that's a separate matter of how to best present those instructions for your users.

[derefr]

I don't think there's any possible way to present the instructions such that people will read them, if those people are in a flow state. People only even read the instructions once their cached reflex of how to do the task doesn't work out for them and they "wake up" a bit.