I think there a lot of people out there. Some are genuinely just thick and don't interpret it as a scam, as you say some elderly and potentially early dementia etc, some having a disability of some kind, or just someone who's really stressed / sleep deprived and not thinking straight.Not sure whether or not to feel sorry for that person or not. Thats pretty much the same as selling something for cash.
scammer: I forgot to withdraw the £300, Ill come back in 5 days with it.
It may be just me, but I can't see how anyone would fall for that. Then again I do see people prying on the elderly and they can be quite forgiving and will fall for silly things. ******* scumbags these scammers.
The thing is, this person I know who got taken for £200 - well, it only needs one person a day to fall for it and you're earning a lot more than minimum wage. I expect a decent scammer could be contacting hundreds of people each day.