yes, u can if u r using session then
where u want any one can access then write code without check of session. if u want that none authenticated user can't perform click button action then u can verify user on button click event.
like\
protected void button(object sender, EventArgs e)
{
if (HttpContext.Current.Session["userName"] != null)
{
perorm what ur button action u want to do
}
else{
Response.RedirectToRoute("HomePage");
}
}
if ur username session is not null then u can perform action, otherwise it will redirect u to homepage.