diff --git a/README.md b/README.md
index 83ec624a..b58c0b5e 100644
--- a/README.md
+++ b/README.md
@@ -201,10 +201,11 @@ async {
 }
 ```
 
-The span `_s` will be dropped at the end of the `async` block, _not_ when the
-future created by the async block is complete. In practice, this means that
-the span does not live long enough to instrument the future for its entire
-lifetime.
+The span guard `_s` will not exit until the future generated by the `async` block is complete.
+Since futures and spans can be entered and exited _multiple_ times without them completing,
+the span remains entered for as long as the future exists, rather than being entered only when
+it is polled, leading to very confusing and incorrect output.
+For more details, see [the documentation on closing spans](https://tracing.rs/tracing/span/index.html#closing-spans).
 
 There are two ways to instrument asynchronous code. The first is through the
 [`Future::instrument`](https://docs.rs/tracing-futures/0.2.0/tracing_futures/trait.Instrument.html#method.instrument) combinator:
diff --git a/tracing/README.md b/tracing/README.md
index 37670db7..ec882845 100644
--- a/tracing/README.md
+++ b/tracing/README.md
@@ -216,10 +216,11 @@ async {
 }
 ```
 
-The span `_s` will be dropped at the end of the `async` block, _not_ when the
-future created by the async block is complete. In practice, this means that
-the span does not live long enough to instrument the future for its entire
-lifetime.
+The span guard `_s` will not exit until the future generated by the `async` block is complete.
+Since futures and spans can be entered and exited _multiple_ times without them completing,
+the span remains entered for as long as the future exists, rather than being entered only when
+it is polled, leading to very confusing and incorrect output.
+For more details, see [the documentation on closing spans](https://tracing.rs/tracing/span/index.html#closing-spans).
 
 There are two ways to instrument asynchronous code. The first is through the
 [`Future::instrument`](https://docs.rs/tracing-futures/0.2.0/tracing_futures/trait.Instrument.html#method.instrument) combinator: