Negative performance impact of access() should be emphasised more.

The warning about the negative performance impact of repeated access() calls from the sync function should be made more prominent. This could be moved to the top of the page, be placed in a warning box to emphasise, etc.

Currently the only warning is under the Context subheading.

But note that, invoking it multiple times to grant the same user access to the same channel, will result in negative performance implications.

Which is quite easy to overlook.