Lookup::dropLookupMode specifies that:

If UNCONDITIONAL is dropped then the resulting lookup has no access.

This happens only if this Lookup object has a public lookup (i.e. UNCONDITIONAL is set) which can be produced by MethodHandles::publicLookup or teleported from a public lookup to any accessible class via publicLookup().in(X).

It has no effect if this Lookup object does not have UNCONDITIONAL bit on.

The documentation should be improved to clarify that.