I think that this article is another example of the lazy journalism that often appears in the UK edition of Runners World. I'm sure you know the kind of thing I'm talking about, where the article first appears in the US version and gets lifted wholesale to be printed over here, without researching its relevance. They might have clocks at every mile in US races, but I've never heard of or seen such a thing over here.
The other thing that bugs me about such articles is that they are often too lazy to take into account cultural differences between us. for example keeping temperatures in farenheit instead of celcius.
After checking the runnrersworld.com website I see that the article first appeared on there 3 days ago.
Any sport is a set of rules and you have to comply with them otherwise what's the point in doing that sport. I don't like the rolling maul in rugby, which I consider to be legalised obstruction, but until the rule changes it just has to be accepted as a condition of playing. Similarly with headphones, if it's a rule in a race you just have to accept it. Disqualification is just a consequence of ignoring the rules wether you like it (the rule) or not..
I would certainly avoid taking the event buses. They are overpriced and there is a long walk from the finish to the bus pick up point, which is often chaotic. Best to stick to using the local bus service. The Nos 26 and 44 are the services you need. They can both be taken from the start at London Road to the finish at Musselburgh. A day pass is £4. An alternative return from Musselburgh is to hop on the cheeky First Bus Service buses that wait outside the finish park exit (not official and not advertised). They wait outside the park, across the road and to the left and it's only £1 to return to the start in London Road.