Sam..
well we get the t-shirts and hats too...my son has been known for years in his school for wearing nothing but disney tshirts (until this year, when they were replaced by funny sayings tshirts)...
but the magnets are as you say, cheap and easy...and we have them from every city and every country we've visited since we started this silly habit of ours....(about 10 years ago)....and we don't lose them...they're right there...on the fridge...
the stupidest thing of all is that when i had to buy a new fridge this year, one of the things i demanded was a door that could hold magnets.....kinda dumb to be sure...but i like kitsch better than house beautiful any day...at least when it comes to our fridge....