I've found a way to do it. Here is the description:

Activate the "Technical features" from Settings -> Users -> Users -> USERNAME -> Access Rights (tab in the form) and check the "Technical features" checkbox and refresh with F5.

After this go to Settings -> Technical -> Actions -> User-defined Defaults. Then click on "Create" and fill in the fields as follows:

Name = opt_out (field name)

Model Name - leave it empty, because the next field will auto fill it

Model = res.partner (you can set also crm.lead if you use CRM module)

Condition - leave empty, because you want in any condition to have the opt_out field checked

User - leave empty if you want to activate this action for every user

Textarea (under Model field) = 1.

Finally, save the action and create a new partner. The field opt_out should be checked by default now.

I have used the same procedure to check this field by default for crm.lead and res.partner models. It works fine.

Hi;

Edit the file .../openerp/addons/crm/crm_lead.py around the line 317 add 'opt_out': 1,

Like:

_defaults = {

   'opt_out': 1,    <------------------- add this line

    'active': 1,

    'type': 'lead',

    'user_id': lambda s, cr, uid, c: s._get_default_user(cr, uid, c),

    'email_from': lambda s, cr, uid, c: s._get_default_email(cr, uid, c),

    'stage_id': lambda s, cr, uid, c: s._get_default_stage_id(cr, uid, c),

    'section_id': lambda s, cr, uid, c: s._get_default_section_id(cr, uid, c),

    'company_id': lambda s, cr, uid, c: s.pool.get('res.company')._company_default_get(cr, uid, 'crm.lead', context=c),

    'priority': lambda *a: crm.AVAILABLE_PRIORITIES[2][0],

    'color': 0,

}

_sql_constraints = [

Update the module crm.

Sory, change it here: openerp/addons/email_template/res_partner.py

Change False to True

_defaults = {

    'opt_out': False,

try with:

_defaults = {

    'opt_out':  lambda *a: True,