So.. no, not really:

```ruby
pry(main)> Rails.cache.write("lolol", nil)                                                                                                                                      
=> true
pry(main)> Rails.cache.read("lolol")
=> nil
[39] pry(main)> Rails.cache.fetch("lolol") { "omg" }
=> "omg"
```

That's a concern of a Memcached cache layer though, not this one. I'll fix it with your suggestion in the built in cache :)