Express Entry system has its own criteria to review the application and each officer needs to follow that, your documents must show everything as per their requirement. It is designed for CIC officers to have to go looking for information, it is designed to be quick and thorough. If you do not provide the required information, clearing and in the manner CIC requests, you may be refused without opportunity to provide more information.
Verification: If they doubt that you might arrange any of your documents illegal manner only in that case CIC verifies. Do not think that CIC is going to verify or ask any clarification if your documents are not as per their requirement.
regards
D