Regardless, I'm not sure what we should do about this issue. Loading readline is obviously provided as a convenience to make the interpreter prompt easier to use. Several of us would probably like to go a bit further and also add tab-completion (see issue5845).

It stands that while the -S and -E option allow to disable any customization a user might have done (which is necessary for e.g. suid scripts), the automatic insertion of '' into sys.path has no way of being undone.