[giantg2]

Most of the time trespassing (which is more akin to this than burglary) requires the owner to post obvious notice or ask the person to leave. I did not see that intentional act here either.

So there's no intentional act by the owner either way. In the physical world, no crime would be committed. It seems this is further reinforced by the fact that AWS documentation repeatedly states that buckets can be accessed publicly or secured depending on the settings. Kind of like the government (in most states) saying people can walk through your property unless you take steps to prevent it.

Yes, judges will laugh at a defendant bringing this up, but will eat up whatever comparisons a prosecutor makes.