Igazából már:
https://tools.ietf.org/html/rfc7231#section-4.2.1 (a 2616 deprecated). Konkrétan annyi változott, hogy most már nem should not, hanem
When a resource is constructed such that parameters within the
effective request URI have the effect of selecting an action, it is
the resource owner's responsibility to ensure that the action is
consistent with the request method semantics. For example, it is
common for Web-based content editing software to use actions within
query parameters, such as "page?do=delete". If the purpose of such a
resource is to perform an unsafe action, then the resource owner MUST
disable or disallow that action when it is accessed using a safe
request method. Failure to do so will result in unfortunate side
effects when automated processes perform a GET on every URI reference
for the sake of link maintenance, pre-fetching, building a search
index, etc.
Vagyis / rfc tilos, kedves sj :)