Presumably the only reason a closed source vendor would be against someone reversing their source is because they're afraid someone will steal their ideas and/or redistribute their code for free.
That not being my goal I really couldn't care less. I'll just go ahead and reverse whatever I want whenever I want. I value my security, and that of clients, over some legal piece of toilet-paper. Everyone who doesn't agree, should reconsider. Do you truly believe that people should not be allowed to look at code that is running on their systems for their security's sake? I will not redistribute what I learnt, but I will analyse it to see if it is safe.
If you didn't want me looking, you should not have put it out in the open.
I was once at a startup and another company in Texas released a product with identical typos as found in our object code.
Selling that software was how I got money to pay rent and buy food to put into my food-hole, so I'm going to feel a little more sympathy for people who want to stop others from reverse-engineering their stuff.