This particular wikipedia article focuses more on the development of ACTA, and public comment and rumour during its development, than it does on the actual text of ACTA, a public document.
I haven't read the actual text, and I imagine that the issue of whether or not ACTA will force border searches is definitively answered by the treaty itself. The Wikipedia passage in question appears to have been written in response to rumours and leaks dating back to 2009.
I've done some more reading since, and my arm-chair legal review seems to indicate that most, if not all, search and seizure happening in this area is due to U.S. policy and legislation and not ACTA. i.e. DHS, etc. have their own policies rooted in US law that seems to permit this type of search and seizure.
I didn't do a thorough analysis, nor am I am lawyer, nor am I an ACTA supporter, and I think that the wikipedia article referenced is poorly written and not thoroughly representative of the current status of ACTA, its powers and effect.
(edit: it looks like some of the other commenters have picked up on this as well - definitely worth a thorough read of all the comments for a more current view of what we're actually getting with ACTA, I found this post especially helpful [1] http://news.ycombinator.com/item?id=3496277)
I haven't read the actual text, and I imagine that the issue of whether or not ACTA will force border searches is definitively answered by the treaty itself. The Wikipedia passage in question appears to have been written in response to rumours and leaks dating back to 2009.