Issue about leave application

Hi, guys
The issue is : When an employee who is a leave approver apply a leave application and choose herself/himself being leave approver, everyone will get message and email.
I checked the code, the reason probably is that there is a condition check in the post function in the messages.py code.
if contact==frappe.session.user:
_notify([user.name for user in frappe.get_list(“User”,
{“user_type”:“System User”, “enabled”: 1})
if user.name not in (“Guest”, “Administrator”)], txt)
I’d just like to know:

  1. Is this condition check used for other situation ?
  2. Can one person choose himself/herself being leave approver ?
    Thank your very much.