o Safety concerns
Fortunately we have an almost untouched paradise just south of the border - and it is untouched in part because many people fear it is not safe to venture into Mexico. So, only few people ever go to explore Baja California - which scientists call the secret Galapagos of Mexico.
Fear of banditos, public safety, dirt and diseases are high on the list of some - police corruption, military harassment and uncertenties in case of emergency concern others.
Actually, the only real danger is to walk into one of the countless, ever-present cacti.
Ouch!
Banditos - there has not been a single report of street robbery in Baja ever. Mainland Mexico is a different story - there have been frequent assaults.
public safety - public safety in Baja (except maybe in Tujuana) is absolutely guaranteed. No gangs, no robberies, no rapes. Be careful in traffic, however. Vehicles may make sudden turns, they may have only one or no light (avoid driving at night) and most major highways are narrow and not always in good shape.
dirt & disease - sure there is dirt, after all Mexico is a much poorer country than the US. But dust and dirt does not translate into disease at all. I consider the public drinking water in Baja cleaner than in most US cities. In Baja all water comes from unpolluted mountain regions. Cheers!
police corruption - used to be. However, about 13 years ago the Baja government decided that police corruption was bad for tourism. They created a hotline to which tourist are able to report any police misconduct. Policemen are so afraid by now to lose their job for mistreating a tourist - they won't even pull you over for a broken tail light. However, if you are caught breaking the law - like speeding - they will stop and fine you. No policeman is authorized to accept money - all fines have to be paid at police stations.
military harassment - just not true. The US government forced Mexico to step up its military presence to fight drug runners. As a result the Mexican military established moving check points on all major highways where all vehicles are stopped and drivers are asked about drug or gun possession (guns are illegal in Mexico). The officers are very courteous and professional. Usually your asked where you come from and where you intend to go - of course you are asked about drug and gun possession as well. Rarely you are asked to step out of your vehicle while an officer is "searching" the car. Searches of tourist cars are very superficial and never last longer than 5 minutes.
emergencies - don't worry you are pretty safe in Baja. Even smaller towns have good hospitals, even rural areas have small clinics. Plus, I found that many doctors were educated in the US. Even if something dramatic should happen to you - you are only a maximum of two flight hours away from US hospitals. Several medical emergency services fly into Baja and transport critical cases home. Good to know - Baja has an excellent network of airports. Sometimes settlements of a few hundred souls have a standard size runway.