Is this a valid tactic?

One side storms a beachhead, but beforehand, they get a bunch of old hovercraft that would have been scrapped otherwise, stuff them with plastic explosives and a load of dumb rockets, and throw them at the beach. When the OpFor realizes the hovercrafts are unoccupied, they throw the dumb rockets at the bunkers stationed on the cliffs overlooking the beach, then detonate their explosives to A) annihilate the frontline bunkers (or at least do some damage) and B) make some cover for the incoming troops with the wreckage.

Considering in the real world they made an entire fake army to help the invasion of France,yes.

That opening barrage from the unmanned craft is unlikely to be very effective. There's nobody around to aim it, after all.

The tactic is very workable, but its greatest use is as a distraction. In fact, you might consider having the fake landing craft hit the beach solo, whilst the invasion force proper lands somewhere else. It's very difficult to rapidly redeploy troops once they're dug in to repel a beach assault, and you'd run less risk of blowing up your own troops when they go in after the dummies.

edited 21st Jan '11 5:20:04 AM by Iaculus

The concept has historical precedent, from sending fire ships into enemy harbours to a variety of unmanned explosive devices designed to clear obstacles. Not sure how effective it would be, especially since the enemy would probably be shooting at the hovercraft as they approach.