Aliasing shibari → rope_bondage
Link to alias

Reason:

Notable idea that's hard to guess the way to search for.

shibari is more than just using ropes, though rope is the most common material. You could use rubber hose or ribbon or something and tie someone up, though it would not be traditional. If anything, it should be aliased to bondage as it is simply the japanese term for it (literally; it translates as "to tie"); the 'erotic bondage' aspect comes from kinbaku, not shibari, though modern usage has conflated the two, and can be equivilently searched with ~rating:e ~rating:q bondage (and for traditional, add rope)

Alias should be rope_bondage → shibari because shibari has 10 times more posts.

DrHorse said:
Alias should be rope_bondage → shibari because shibari has 10 times more posts.

Getting rid of the shibari tag altogether wouldn't make sense at this point.
Since shibari is a type of rope bondage, it seems like it should imply rope_bondage. Since it is its own distinct thing, arguably, aliasing it to rope_bondage wouldn't be as helpful as just having it imply rope_bondage. This would also solve the same problems for searchers as Squir's proposal.