Autozen,

I'm pretty close to your thinking.

You can get a leak stop detector. That means that to protect your recovery equipment, you need about $2000 worth of identifying equipment, a refrigerant identifier and a leak stop detector to protect several thousands of dollars worth of equipment.

I don't have an identifier, so I just don't let my recovery machines get anywhere near a car that I don't know anything about.

The people who put in refrigerants without proper labeling and fittings usually have no idea what kind of problems they are causing for others or they just don't care.

Have a great day,