I'm not the least bit worried about Neteller absconding with my funds.
Two worries I do have:
1. Some computer / technical glitch wipes out all their records of how much money I have on account. With the backup systems I assume they have in place, it's highly unlikely this will happen.
2. A bigger concern is the fact that, depending on which book you deal with, some websites ask for your Password while others ask for your Secure ID. Theoretically, two books (or, more likely, two employees from separate books)could combine forces to get access to your account and your money.