No.

Conventionally, "bang" methods should only be created as 'dangerous' versions of non-bang methods. There was no non-bang method to make a 'dangerous' version of in this case so it's non-bang by default. This is a commonly misunderstood naming convention in Ruby (and I dare say I don't even understand all the intricacies!)

There are quite a few examples of this in Ruby. For example, Array#keep_if which changes an array in place.

I guess I misunderstood your definition of "in place". That jives with what I've understood about Ruby so far.

That would be redundant, since there would be no difference from String#+.