Understanding the model, initial/default value

[Brown, Berlin [GCG-PFS]]

Panel.java:
...
 final IModel<Boolean> modelForAgree = new
Model<Boolean>("yes".equalsIgnoreCase(obj.getAgree())));
 
form.add(modelForAgree);
...
 
In this code, how can I ensure that modelForAgree has the right default
value when the panel loads.  Is it possible that the Panel gets
deserialized with an older version of modelForAgree?
 
Berlin Brown