Can An Lc (letter Of Credit) By Any Means Be Compromised?

Please i would like to get an articulated and constructive answers from Bankers in here. And also lets put sentiments apart we are all Nigerians so let tell ourselves the truth.

Folks into exportation of Raw material from Africa can agree with me that many foreign companies hardly accept  to advice their LC down to Africa, especially Nigeria when it comes to first time business. And many bank will warn you or probably refuse you each time you ask them to tranfer an LC down to Africa.
The main reason many gave was the corruption and fraud in Africa and mostly from Nigerian Banks.
So can an LC  be compromised or turned into an unlawful benefits to the receiver? Am meant to understand its jst a telegraphic advice which can be revoked or concelled if the terms in it are not being met.

Any other justified reason can be accepted.