https://fedoraproject.org/wiki/Packaging:Guidelines#Scriptlets_requirements
AFAICT the last bugs related to comma separated scriptlet dep syntax like Requires(pre,post,...) were fixed in rpm 4.7.1, so I suggest removing the "Scriptlets requirements" paragraph altogether, or leaving it in but noting it only concerns EL5 nowadays.
(Originally posted on list, got no response there. https://lists.fedoraproject.org/pipermail/packaging/2014-January/009924.html)
Section removed from guidelines and added to the EPEL wiki page. Announcement text:
"""
The Guidelines contained a section stating not to use "Requires(post,pre):" type syntax due to rpm bugs. Since those bugs only apply to the rpm shipped in RHEL5, the prohibition has been removed from the guidelines.