Key values starting with .

Hello, I have a url that ends with ?.value=1, but PHP returns this in $_REQUEST as _value instead of .value. I believe this is because of this code: main/php_variables.c

104         /* ensure that we don't have spaces or dots in the variable name (not binary safe) */
105         for (p=var; *p; p++) {
106                 switch(*p) {
107                         case ' ':
108                         case '.':
109                                 *p='_';
110                                 break;
111                 }
112         }

I can do this: $_REQUEST['.name'] = "testing" then if I do print_r($_REQUEST) prints it out as .value and not _value. Any reason for being able to do one, but not the other? Also what is the "(not binary safe)" part of a variable with a . in its name? Thanks, Brian