At ArcGIS Desktop (advanced) 10.3.1, I've created a model that simply copies a file geodatabase. Both the source and target locations are parameterized. Here's a screen shots of the model:
And here it is in action:
Here's my problem: the tool overwrites any pre-existing .gdbs with the same name in the target path. I want to modify the tool so that it notifies the user prior to overwriting. How can this be done? Nothing in the Copy tool instructions or environment settings solves the problem.