Magento 1.9 disable plugin for specific ip - magento

Question

I've got a Magento store (1.9) with a very simple plugin. It changes the customer group when someone places an order in a website. But we also work with a POS.
In the POS the plugin is also trying to change the customer group but it gives an error.
So what I want to do is disable the plugin for our local IP (or User).
The code is the following or check Github:
observer.php
<?php
class RvdH_GroupChange_Model_Observer
{
public function changeGroup(Varien_Event_Observer $observer)
{
$order = $observer->getEvent()->getOrder();
$customer = Mage::getModel('customer/customer')->load($order->getCustomerId());
/*$event = $observer->getEvent(); //Fetches the current event"
$customer = $event->getCustomer();
$dbcustomer = Mage::getModel('customer/customer')->load($customer[entity_id]);*/
// ensure it's not guest checkout
if ($customer->getId()) {
$customer->setGroupId(5);
$customer->save();
}
}
}
config.xml
<?xml version="1.0"?>
<config>
<modules>
<RvdH_GroupChange>
<version>0.1.0</version>
</RvdH_GroupChange>
</modules>
<global>
<models>
<RvdH_GroupChange>
<class>RvdH_GroupChange_Model</class>
<resourceModel>module_mysql4</resourceModel>
</RvdH_GroupChange>
</models>
<events>
<sales_order_place_after>
<observers>
<RvdH_GroupChange>
<class>RvdH_GroupChange_Model_Observer</class>
<method>changeGroup</method>
</RvdH_GroupChange>
</observers>
</sales_order_place_after>
</events>
</global>
</config>

Answer 1

Solved.
I just had to change the <global> tag to <frontend> in the config.xml.
Now it only works in frontend and not global.