according to different observation i think few ways are available for abusing bitcoins transections such as Technical weakness , Greedy peoples ro dishonest people , proper management. i would like to describe above mentioned quotatin in briefly
1. technical weakness: we know its a peer to peer transection system throgh confirmed way. within a few second a dishonest person can get more money by fast clicking when submit second payment of different recipient.
2. proper management: there is so many lack of proper management of human or account holders. so many hackers want to hack system for getting money because bitcoins holder don't have any insurance like bank account holders. even government don't follow rules and regulation for virtual currency holders.
So what you think about it ?
As far as I know improper usage of Bitcoin only define when it is used in any unlawful activities such as used fund terrorists, trade for drugs, frauds, scams and any crime related activities commited by lawless elements. For me security related issues sometimes do not belong to improper usage due to recklessness and carelessness of the owner or holder of the specific coin. But whatever it is as long as it cause damage or loss to each and everyone of us it can be prevented and could be our greatest responsibility of our own asset. So be aware and be a responsible holder, owner or investor to avoid loss.