Conditional display of a Views field
By conditional field do you mean a simple Boolean? If so, you should be able to pull this off with some tactical field rewriting. 

When creating the Boolean in your content or entity type, have 'Yes' as the only value, leaving the unchecked state assumed as no. Then in views add the flag list field first and exclude. Next the Boolean but don't exclude. Use its default formatting not its key. In its settings rewrite using the flag list field replacement pattern, and in the empty behaviour (eg the result of the empty checkbox when no value has been specified for it), choose to hide rewriting. 

You may need to fine tune this or perhaps add additional fields, chasing the replacements until it works. You'll be amazed at the sophisticated conditions you can set up in this fashion.