Babel preset es2015 loose not working? - babeljs

Question

Is this "loose": true not working for the "es2015" preset or a mistake/misunderstanding on my part?
Input Code
I've tried with the REPL and on on the command line. I can't get babel to translate my loose javascript in looseWith.js:
var obj = {};
with (obj) {
}
.babelrc (attempt1):
{
"presets": [
[ "es2015", { "loose": true }]
]
}
.babelrc (attempt2 - as in REPL):
{
"presets": [
"es2015-loose"
]
}
I then try running either of these .babelrcs:
> babel looseWith.js
SyntaxError: looseWith.js: 'with' in strict mode (2:0)
1 | var obj = {};
> 2 | with (obj) {
| ^
3 | }
Seems to me that this is still in strict mode. The documentation on loose is quite scarce and just says:
Enable "loose" transformations for any plugins in this preset that allow them.
I'm trying to negate use strict :-) Is this my misunderstanding? What other meanings are there for "loose"?
I then tried adding "modules": "umd" to .babelrc to attempt1 above, and when fed with a proper strict .js file, it did produce umd output, so I think babel is picking up the .babelrcmodule just fine.
Background
I'm trying to be able to use ES6 in my underscore/lodash templates. The javascript output of e.g. _.template(script).source contains the "with" statement (by default). So I'm trying to use babel to translate ES6 - including the "with" statement - into ES5.
Environment
> node --version
v7.10.1
> cat package.json
{
"dependencies": {
"babel-cli": "^6.24.1",
"babel-core": "^6.25.0",
"babel-preset-es2015": "^6.24.1",
"babel-preset-es2015-loose": "^8.0.0"
}
}