It looks like you are using adblocking software. I understand that ads are annoying, but this is one way for me to make a living on this site. As an alternative you might consider becoming a donating member. All ads are removed automatically for donating members.
2002 CF: 2004 from Paris: 2006 VF: 2007 CF: 2009 Aragones, Ingles, Finisterre: 2011 X 2 on CF: 2013 'Caracoles': 2014 CF and Ingles 'Caracoles":2015 Logrono-Burgos (Hospitalero San Anton): 2016 La Douay to Aosta/San Gimignano to Rome:
It could depend on the hospitalero - one might say OK and another say "No!"
I don't think it's right to turn a pilgrim away when it is their first day. Thousands catch a bus to Roncesvalles and stay in the albergue there with no problem.
What time do you get there?
If late, the albergue could be full. In which case you could book a place ahead of time.
If early, you could walk on to another albergue.
The night I stayed in the albergue in O'Cebreiro, it did get full, and they rigidly applied 'priority' there. The cyclists who wanted to stay had to wait until quite late -maybe it was even after 8pm- to see if there was room. A couple of groups, including teenagers and adults, arrived by taxi to begin in O'Cebreiro. They were lowest in priority, and one of these family groups ended up sleeping outside the albergue, on what was a very chilly evening on a mountaintop. However, if you have walked 5km, you have walked at least something, so as sil says, it might then depend on the hospitalero.