Siemens isn't the bad guy here. In many countries, bribery is just how things are done. If everyone does it, then you will get the order if you have the best bribe. Walk around a country like that preaching your morals, and you won't get an order. Salesmen were just doing their job. That's why corporate provided the cash.
To look at it like Siemens is the bad guy, is to say they need to correct every culture they try to sell in.
Personally, I'm against bribes. It certainly violates my ethics. I just want to lay blame where it's due. Evil in the world, etc. Singling out one company misses the broad picture.
Regarding lunch, If the salesman does his pitch during working hours, the boss is paying for my time. If he wants to pitch me during lunch, he needs to pay me for taking up my personal time. The cost of lunch is less than my pay, but it's a friendly and relaxed setting. The salesman is getting a good bargain. It is not a bribe.