As a rule "NO", at least in my facility. Granted there are times when some of our rural EMS squads have been known to board and collar some patients who may not necessarily need it. Example :little old lady who slid out of recliner onto her bottom on a carpeted floor.
That being said, without the proper x-rays and clearance you can never be sure of what underlying injury may be present. Spinal injuries are generally the sort of thing that can't be "eyeballed" even by the most seasoned nurse. JMO.
Finally, I wouldn't want to be the one responsible for exacerbating an exisiting injury, would you???
And if it's your patient and someone takes them off the board or orders them off document, document, document!
Good luck to you