Some actors hate last minute auditions. We call you at 10am and say "you need to get there before noon!" its a frantic race for all involved, changing schedules, getting out of work or school. learning your sides etc.
Dont blow off last minute auditions if you can help it. There is less competition, some people cant get out of work or just cant make it with little time. Also if they give you a last minute audition they usually have hand picked a few people for the job.
We just had a client get a last minute same day audition. She only had 4 hours to get to the audition and decided not to go. I got a call from the casting director very upset that she was the ONLY person they called in. They just wanted to make sure that she did in fact look like her picture. The casting director was very upset as was I. The reason for missing? She had a conditioner in her hair and didnt feel that she had enough time to blow dry it. To that I say throw on a cap and run in. Casting directors are smart, they can see the potential if you are rushed into an audition.