I've observed on Tiki 7.0 that neither using the semantic alias syntax
On page foo: (alias(foobar))
as described on
nor using the page alias function of the structure feature (it's called »Seiten-Alias« with german i18n, but I think the english i18n uses the term »page redirect«) will actually create redirects.
However, if users try to create the wiki page »foobar«, they're notified that this name is already a redirect to page »foo«.
The semantic-links-feature is switched on, of course.
Thx & regards,