This is my survey of stations I have seen since the new policy - Rocky Mount, NC - doesn't seem to make any difference - the station is used for other uses as well as Amtrak and it is still totally open to the public as far as I can tell.
Greenville, SC - the station is in the NS yard and has always as far as I can tell not been open to the public.
Spartanburg, SC - the station was labeled as a visitor's center, but did not appear to be very welcoming to visitors since it was totally locked up - I'm not even sure if the station is still open, it seemed rather deserted so Amtrak might have moved to a different location - I really didn't have a lot of time to linger.
Gastonia, NC - the station is also at an NS yard - there were no trains present so I didn't stop. It probably is not open when NS is active since it is a station where only one train stops late at night and it is also in a NS yard.
High Point, NC - the platforms do appear to be off limits - the station is still open to the public. The tracks are not really visible from street level.
My reading of the Amtrak policy was that out of those listed stations, only the Rocky Mount one and the Spartanburg one if is it still the Amtrak station whcih I really couldn't tell would not be covered (Rocky Mount's station is city owned and open to the public as an attraction complete with rolling stock display on the platform and a museum inside). High Point would be covered because the platform is separate from the street and labled only for passengers only. I think that Gastonia and Greenville would not be covered, but still not open to the public because they are both on NS property.
Other stations I am familiar with - Ashland, VA - is a visitor's center so should still be open - also it really does not qualify as a platform.
Ettrick, VA - may be closed off, but not sure.
Richmond Staples Mill Road - probably closed off
Richmond Main Street Station - Platforms have always been closed, but station which is owned by the state has been open with historical displays and as an attraction and has an open porch on track level at the front of the building
Fredericksburg, VA - its always been open and unmanned as far as I can tell - CSX may still own the station considering that VRE stops there and there are machines to buy both Amtrak and VRE tickets on the platform, you can probably get away with being up there. Last time I was up there was before the new policy, but I got absolutely no hassle from anyone for being there.
Alexandria, VA - think that station has been generally closed to the public but not sure
Washington, DC Union Station - the platforms have long been closed to the public - no difference.
Staunton, VA - the station is unmanned open to the general public and is considered a visitor's attraction - no difference.
Danville, VA - station is now a museum - last time I was there, the platform appeared to be open to the public but that was a few years ago.
Selma, NC - station is advertised as an attraction on I-95 and contains a historic exhibit - doubt that anything has changed.
Hamlet, NC - station is a museum/attraction - railroads are the primary attraction in Hamlet, doubt that anything has changed.
Southern Pines, NC - station has always appeared to be open to the public - think it is a visitor's center - last time I was there, there were some people standing on the platform waiting to see a freight train go by - I actually didn't wait there because a better view was available
Baltimore Penn Station - again, the station has always been open and the platforms were always closed - do not see a difference
Rockville, MD - that is really a MARC station and it is totally open (it is a flag stop on the Capitol Limited) - I've gone on there once to photograph a MARC train with no problem
That is my quick survey - it seems that most of hte stations with platforms that were not open to the public (e.g. Washington Union Station, Baltimore Penn Station) are off limits without tickets - the stations that were always open to the public appear to still be open and while the Amtrak policy seemed to be a bit confusing on that regard to me, it seems that the jist of the matter is that places that have traditionally been open to the public (such as a city owned station/visitor's center/museum) will still be open for photographs. At least that is as far as I could tell.