Description:
------------
Php suppresses the backslash before left curly brace using
"action at distance", violating the "principle of least surprise".

Apparently the backslash is suppressed if there is any non-escaped dollar sign any where in the string.  

Reproduce code:
---------------
<?php

echo ("$     \{    \n"); 
echo ("      \{   $\n"); 
echo ("      \{$   \n");
echo ("      $\{   \n");
echo ("      \$\{  \n");
echo ("      \{\$  \n");
echo ("\$    \{    \n");
echo ("      \{  \$\n");
echo ("%     \{    \n");
?>

Expected result:
----------------
$     \{      
      \{   $   
      {$         
      $\{     
      $\{  
      \{$  
$    \{    
      \{  $
%     \{    

Actual result:
--------------
$     {    
      {   $
      {$   
      ${   
      $\{  
      \{$  
$    \{    
      \{  $
%     \{