Well the only accounts of Hobbits going to Valinor that we are told about were Bilbo, Frodo, and later Sam. So, I don't think that Gandalf actually did send little Hobbit lads and lasses to 'blue shores.' There are a few explanations I think though:
1) Tolkien was constantly trying to get
The Hobbit to fit in with the Lord of the Rings. For as we know The Hobbit started out as a bedtime story to his sons, and some things he just put in there to kind of 'spice up the kid's tale.' Therefor, we would be making too much of it.
2) I think another possibility is that was a fabrication going around created by the Hobbits about Gandalf. As we know the Hobbits really began to dislike Gandalf's company in the Shire and they would go to blame him for Bilbo's presumed 'madness.' Perhaps this was simply a lie the Hobbits started about what Gandalf did...you know one of those scary stories your parents tell you to make you frightened of something. I can just see hobbit parents telling their little ones
'Watch out if you're bad big, ol' whacked out, funny looking bearded guy is going to come and ship you away from your home! So be good!' 