Hosanna filio David - silenced?

There seems to be great confusion between the different entrance possiblities on Palm Sunday. I have suggested that our schola sing the Hosanna filio David - but modern rubricists seem to have clever ways of doing away with any vestage of tradition yet again.

With practicality in mind, people in our parish will be given palms to hold before they gather in the church, and there will be no procession per se. Is tradition being eschewed under the guise of modern functionalism? Is this the reason for opting for the less than ideal "Solemn" entrance? If that is the case, then, functionally speaking, the procession will still happen, but informally. Would it be a violation of anything to sing the opening antiphon at this point, i.e., just prior to the blessing of the palms, since the people have arrived at their appointed destination?

The Graduale lists the Hosanna filio David as the opening antiphon for the ceremony of the blessing of the palms. Elliot's contribution is extensive but doesn't take into account modern, functionalist thinking. Here is another case where settling for less than the ideal conveniently does away with a ceremony geared at, of all things, active participation in the liturgical drama. The irony!

Maybe I'm grasping at straws...but it sounds like another clever way of bypassing the contents of the Gradual..