concert going

[pianoplayer51]

Ive booked to attend a piano concert.   I am very curious because when I look online at the seating I can see that nearly all seats are sold.   The next time I look, a number of seats are for sale so that means that people who booked those seats have relinquished their tickets.    You cannot get a refund for your ticket unless the concert is cancelled  so I am curious to know why now when I look, there are at least 9 seats for sale when previously there were only two.

[faulty_damper]

It's possible that season ticket holders sold their seats.  Another possibility is that unsold seats are on reserve while they are browsing the site.  If they don't check out, it goes back on sale.

[quantum]

Online buying of seats can sometimes lag behind the actual number of seats available.  Buying in person at the ticket booth will often provide more up to date data. 

Another reason for dependencies are "comps" or complimentary tickets.  The artists performing may be issued a given number of comps for friends or associates.  These may also go to corporate sponsors, various VIP's, or people associated with the concert venue.  Sometimes these people cancel, or are no-shows.  I've been to "sold-out" concerts where there were entire rows of empty seats. 

Some venues also have pick-up deadlines for certain types of tickets.  Eg: student discounted tickets.  If the person does not pick up the ticket by a set time, the seat goes back on sale. 

Venues may have what are called "rush lines."  Close to the concert start time, say 15-20 mins, the venue may release any unclaimed or empty seats to those willing to wait in the rush line.  This is of course a gamble, as one never knows if or how many of these seats will become available.