To some extent, yes. However, there are many places in the LEED Online forms where the signature of a specific project team member, such as the engineer or owner, is required, and the LEED AP can't sign off on these indiscriminately.
Xavi, You will find all clarifications in the ( LEED Certification Policy Manual For Use with All LEED Rating Systems and Participation in All LEED Certification Programs), June 2011 is the latest version.