Think its a good opportunity to be positive. Use the training to do another marathon, on the same day is good, plenty on link Fido provides!
AND, because its not London it won't cost your charity the £500 or whatever London charges these days, so all funds raised go to the charity and not to the London (who I am so not a fan of; just my opinion, but I think they rip all the charities off for as much as they can - but, just my opinion)
Agree its very antisocial to drop wrappers, only race I do that has a plan is Stamford 30K where they put a rubbish box at every K marker and ask that all runners use them, which makes things a bit better.
Perhaps if the race organisers raised awareness re dropping stuff and provided the means to do it things might improve.
Personally I always hand/throw any stuff to a Marshall, am sure they really appreciate it.
Wear headphones if you want to - perfectly within your rights, why should anyone tell you what to do if it only affects yourself.
But, organisers have same rights, and can and will disqualify you if they want to.
Met a runner before Bedford half who insisted that he would wear headphones, said he didn't care if he got disqualified, as organisers threatened to do - dunno what happened - and whats more don't really care, headphone wearers can do whatever they want, not my concern, just don't complain afterwards.