Remember that tourist card that you took the trouble to get stamped at the border in Tijuana? Well, if Emigration is ever going to check it, it will be here in Guerrero Negro:
Once, I didn't have the tourist card stamped (you can pick up the tourist card in the U.S. but you can only get it stamped at the border in TJ or in Ensenada). I was told that I had a week to go to a bank, pay the fee and get my card stamped. That was it. On another occasion a young friend of mine flew into the U.S. without a stamped tourist card. In the airport, at the emigration check, he was pulled out of the line, escorted all the way past everybody to the bank in the airport and required to pay for the fee (I think he had to pay a small penalty as well). I think he may have done okay- he had to pay the tourist card fee but he got to bypass the long line.
Baja Tip: Just take the time, pull over at the border and get the paperwork squared away. If you do that, you'll have no worries. If you don't, in my experience, not much will happen to you... but why risk it?