I have already made the point, which seems to be ignored, that safety standards on UK railways are negotiable rather than absolute. Thus there are stations (I cited Silverdale as an example) where despite it being indescribably dangerous and stupid for a passenger to be on the track anywhere in any conceivable circumstance, according to some commentators, you actually HAVE to cross the track to use the Lancaster-bound platform. This could be resolved by building a footbridge, or purchasing land to give access to both platforms from the road, but basically Network Rail are prepared to take the risk that somebody might get mown down by a train here going about their lawful business, and this is duplicated at many other places. Or take DOO, overcrowding, footpath crossings or third rail electrification - suffice it to say that cheapness and economy can and do officially trump safety on the railways.
Now this is NOT to say that jumping down on to the track at a busy main line station like Doncaster is a safe and wise thing to do - you do run a slight risk of a fatal accident if you fail to keep adequate watch and are not very nimble, as you do every time you legally cross a busy main road, but you run a very large risk of some nearby railway employee thinking that this ought to be brought to the attention of the subservient in-house police force which the railways somehow manage to maintain, with a resultant prosecution, under trespass laws which don't apply in any other comparable public place. So, no, don't do it.
All this is to do with taking a risk v reward approach which many of us do on a daily basis, but bear in mind that, as other commentators have admitted, obtaining railway employment requires one to submit to psychometric tests which would weed out anyone more suited to, say, a creative approach to work (that's being discreet). And bear in mind that a substantial number of these commentators also are rail employees themselves, which would preclude them from taking a common-sense approach rather than a rule-based one, and that they may be identified from their participation in these forums. So don't expect anything approaching rationality, and do expect plenty of abuse saying you're an irresponsible idiot, etc - they're used to treating all members of the public like morons just because a few are.
But generally it's NOT a good idea to venture on to the track, particularly from a platform edge, but I would consider the value of what I'd dropped versus the likelihood AT THAT LOCATION of encountering a train I couldn't see or hear adequately or encountering a modern-day rail employee or being picked up by a CCTV camera. Just take care.
OK, I am not and have never been a railway employee. My only involvement with the railway is under the contract that every passenger agrees to when they travel. If you break the rules, you can be prosecuted for them. It is no more reasonable for you to argue that certain rules don't apply at certain locations or to certain passengers (e.g. you) than it is OK for you to ignore the speed limits on the road, or the use of phones in planes etc.. Your judgement is not in question here, in fact if there are specific rules, your judgement is irrelevant. If you can't accept the rules then don't travel on the railway.
The health and safety rules are not perfect, and in a (very) few instances, they can confuse some people who claim to have superior 'common sense' which means that they act in their own interests alone. As has been mentioned above, causing an emergency braking at less than 10mph can result in multiple injuries where innocent passengers are ready to alight. In the case of elderly or infirm passengers, it could even be life threatening. But that is OK with you as you have made a decision based on 'common sense' and of course that is infallible. In such a case, I can't see who the poor injured passengers could claim against unless it was the driver's fault for reacting to protect a pratt on the track in front of him.
'Know-it-alls' are far more dangerous than 'know-nothings' in the real world.