All my Web forms have by default validateRequest=true. So, this enables a security that an HTML tag cannot be included in a field. When that happens, .NET doesn't go into the regular events and fires only Page_Unload() followed by Page_Error(). The message is:

"A potentially dangerous Request.Form value was detected from the client"

When that happens, I would like to redirect to a custom page saying something about it. But, .NET doesn't make Request and other objects like that available. So, how can I redirect to a page if I cannot get a handle on Response?