Python:

from openerp.osv import fields,osv

class stock_picking(osv.osv):
    _inherit = 'stock.picking'

    def _available_status(self, cr, uid, ids, name, args, context=None):

        res = {}

        for picking in self.browse(cr, uid, ids, context=context):
            available_status = True

            for move in picking.move_lines:
                if move.state == 'waiting' or move.state == 'confirmed':
                    available_status = False

            res[picking.id] = available_status
        return res

    _columns = {
        'available_status': fields.function(_available_status, type='boolean', string='Completely Available', store=False,),

    }

 

# https://bugs.launchpad.net/openobject-addons/+bug/1169998

class stock_picking_out(osv.osv):
    _inherit = 'stock.picking.out'

    def __init__(self, pool, cr):
        super(stock_picking_out, self).__init__(pool, cr)
        self._columns['available_status'] = self.pool['stock.picking']._columns['available_status']

XML:

<record model="ir.ui.view" id="stock_picking_out_form">
  <field name="name">stock.picking.out.form</field>
  <field name="type">form</field>
  <field name="model">stock.picking.out</field>
  <field name="inherit_id" ref="stock.view_picking_out_form"/>
  <field name="arch" type="xml">
    <data>
      <h1 position="before">
        <field name="available_status" invisible="1"/>
        <h2>
          <label name="do_warning" string="WARNING: This Delivery Order is not completely ready to deliver."
                 attrs="{'invisible':[('available_status','=',True)]}" style="background-color: red; color: yellow;"/>
        </h2>
      </h1>
    </data>
  </field>
</record>

Result: