Create simple bin data:

> db.uuid.save({_id : new BinData(3, "Y0pfMW5Mb2pT1uz5+u1Ckw==")})
> db.uuid.save({_id : new BinData(3, "okiGox+XG637qdDet1rinw==")})

Correct: An example that correctly returns the document:

> db.uuid.find({_id : new BinData(3, "okiGox+XG637qdDet1rinw==")})

Error: If I forget the "new" then instead of zero docs I get all records:

> db.uuid.find({_id : BinData(3, "okiGox+XG637qdDet1rinw==")})

{ "_id" : BinData(3,"Y0pfMW5Mb2pT1uz5+u1Ckw==") } { "_id" : BinData(3,"okiGox+XG637qdDet1rinw==") }