Well, seeing brackets in a URL like that is common: PHP requires those if the <form> field in question can have multiple values, as is the case with checkboxes. That is, a PHP <form> might look like this:
<form action="whatever.php" method="get">
<input type="checkbox" name="food" value="apple" />
<input type="checkbox" name="food" value="banana" />
<input type="checkbox" name="food" value="canteloupe" />
So clearly browsers need to be able to handle field names with brackets.
(Usually, PHP forms would be method="post", but there is certainly no requirement that they be.)
My question to you: Why do you try to remove the ? Are you saying that sometimes they are *NOT* present?