Hi Jools
Sounds like it may be a reaction to what happened last September at the police office in Tortosa.  I had to renew my residencia last September and the only way to get to see somebody was queue up at least 7 am to be one of the 50 people which, we were told by the police receptionist, would be guaranteed to be seen.  The unofficial queue was run by a team of east europeans who had a list system and surprise surprise, there were at least 50 names already on the list when I got there although there were only 5 or 6 people already in the queue. I duly added my name as the 51st person on the list.  I tried to buck the trend however, and queue behind the 6th person, but within the hour before the police office opened I was openly pushed and jostled to the back as more people whose names I assume were before me on this list, turned up at leisure. Of course, I was lucky to get seen that day as a couple of people ahead of me were removed from the queue seemingly their papers were not correct.  It was an awful experience.  The ticket machine was intentionally out of use and the queueing system was the only way to get seen at that time.  Maybe there is an extra influx of 'extranjeros' into the area during this month every year, perhaps for seasonal work.  I know that the staffing levels in the police office are low due to holidays etc. at this time of year.  What was surprising was to be told by 2 English acquaintances that they had had no problem in obtaining their residencia renewals when they visited the office at the end of September last year. They just waltzed in at around 10.30 and picked up a ticket and were seen straight away. So it could just be a seasonal way to deal with additional work at the police office.
Rob