text: **3.6.1. Data alterations and financial sustainability**
  
  Some concerns about the limits of Open Data are about what may happen, or stop to happen,*before*
  
  they are published online. The most common concerns of this type are (from Open Public Data: 
  
  Then What? - Part 1): 
  
  1. Opening up PSI causes those data to not be produced anymore, or to be only produced as 
  
  private property by private corporations, because the public agencies whose job was to 
  
  produce those data, can't sell them anymore. 
  
  2. total accessibility of data provides more incentives to tinker with them, at the risk of 
  
  reducing trust in institutions and inhibiting decision-making even more than today. 
  
  Data manipulation is the topic of the next paragraph. Speaking of costs, a point to take into account 
  
  is that, once data are open, routinely used and monitored by as many independent users as possible, 
  
  even the cost of keeping them up to date may be sensibly reduced: in other words, in the 
  
  medium/long term Open Data may reduce the need to periodically perform complete, that is very 
  
  expensive, studies and surveys to update a whole corpus of data in one run. 
  
  Besides, and above all, even if opening data always destroyed any source of income for the public 