Indent Guides: by default on or off

[sunderme]

The new indent guides (#4123) are common in programmer's editors. They have been asked for for txs and are now available.
Should they be active by default ?

[octaeder]

main reason to let it be ON by default: The user immediately sees and uses the new feature. Otherwise even user who (would) like this feature may not use it just because they are not aware of the new option. All others will look through the options to deactivcate the feature.

[sunderme]

not much participation
I have turned it on by default