Book Two - Dursleys and the pink pudding

One of the things I was most relieved about in Harry Potter book one, was that as soon as Harry went to Hogwarts, the Dursleys faded into the background.  

I started book two, with a feeling of 'we've been here before', Harry is back with the Dursleys, Petunia is being as irritating as ever, Harry's wizarding gear has been locked in the cupboard under the stairs, Vernon is as overbearing as usual, and Dudley is just Dudley!

Even Hedwig is imprisoned - locked in his cage to stop him carrying messages.  Harry's Twelfth birthday is made even more miserable by Vernon holding a dinner party for a 'very important' customer - packing Harry off upstairs where he is told not to make a sound. 

Just as I was thinking it couldn't get any worse, the hedge grew eyes, and Dobby the house elf  appeared begging Harry not to go back to Hogwarts, but refusing to explain who he was working for of what the specific threat to Harry was.  Dobby has also stolen all the letters posted by Hermione and the Weasleys, which seemed a particularly unhelpful thing to do.

Last but not least, Dobby, for no particular reason casts a Hover Charm on Aunt Petunia's pudding - 'a mountain of cream and sugared violets' raising it up to the ceiling, and when asked nicely by Harry to stop, just drops it on the floor.   

Almost immediately a letter arrives by barn owl during the after dinner mints.  Addressed to Harry, the letter informs him that the Ministry of Magic 'has detected the improper use of a hover charm at twelve minutes past nine', and Harry is in trouble.  

It occurred to me that if the Ministry of magic could detect and locate the magical incident, and identify the precise time and nature of the charm employed - surely they could tell that it was done by Dobby the house elf, not Harry. - This seems a bit unfair.