I know this is an older article, but wanted to throw my two cents in. As Martha Alvarado-Castaneda said in her comment lower down, front yard parties were not the norm within my family either.
It was always backyard parties, or "side" yard parties (if your home was the kind that had a garage towards the back of the house and left a huge drive way all the way from the front to the rear).
You need to keep in mind that "Mexican Parties" can get pretty big. It's a big welcome-fest with friends, family, neighbors all being invited. With them coming along, you will also have their guests friends and family tag along. You may even see a few of those friends and families friends, family and friends make it to the event. Redundant use of words, but necessary. The scope is large when it comes to "Mexican parties".
That said, many Mexicans live in large cities, or just on the outskirts of large cities. Learning this from visiting relatives visiting in such cities, I noticed that a lot of these homes in these areas have little to no backyard. You are lucky to have a 15 x 20 yard (which is the size of a small living room in many homes) but will more than likely find just enough room to squeeze and stack unwanted items in the backyard. You also have to take into account that Mexicans love trees. You will usually find a Lemon tree, one or two Guayaba (guava) trees (because you need both the pink and the white/yellow ones), and possibly and avocado tree.
When you have a ton of junk and trees filling up the back yard. Kind of tough to party.
So... you party in the front yard. That way all who come, can fit. The front yard and street become a dangerous, but useful playground as well. As a Mexican, what can you do to make that playground safer? Buy a home in a cul-de-sac.
Let's face it though. Mexican's aren't always the best people to contact regarding safety. We still live by a "Survival of the fittest" mantra, and if you get hurt... you better hide it, or get your butt whipped for being a pendejo and get a parental hurting for getting hurt.