The points about risk assessments and if ramps are so dangerous, why they have not been removed (or fenced off in some way) - if it is, they should be asap, not just when platforms are extended. A lot of stations don't even have a sign advising you not to go down the ramp. And yes, some will argue that "it's obvious" people shouldn't - but is this really the case, when there are still some stations where you actually have to go down the ramp to get out, and it was considered perfectly acceptable in the past.
I realise though that as a driver that removing ramps isn't your responsibility!
The difference where a ramp is part of the station access is that, apart from that it's often provided with a physical barrier, the arrangement is part of the station, and therefore there's a *need* for passengers to be there. Elsewhere, there is no requirement for public access as no train should be stopping there, so it makes sense for the 'passengers must not pass this point' sign to be at the top of the ramp. (What I don't understand is why some places have the sign further along than this for no real reason other than perhaps where that's where the nearest convenient post is, and in some cases where you get doors occasionally stopping in the intervening area).
Personally, being honest I'm not really bothered if someone is standing slightly onto the ramp providing I can see they're obviously taking a photo, my greater concern is that they're not too close to the edge. The difficulty is that drivers tend to operate on an element of autopilot due to the repetitive nature of the job, and because these areas are signed as out of bounds for logical reasons, by definition it's out of the ordinary to see someone standing there. It's all too easy for this distraction to lead to something being missed or overlooked whilst you're spending a few moments looking at what the person is doing and working out why they are there. This could end up contributing to a SPAD or similar, or result in the driver emergency braking the train if they decide the situation looks like, for example, a potential suicide.
Ramps are better for track staff as if you've just carried a load of gear half a mile down the track, it's more convenient to walk up a ramp than up stairs. However it seems the risk of trespass nowadays outweight this.