Any reason not to enable 802.11r/k

[jim_michael]

We have a lot of iOS clients on our wlans and I'm wanting to know if there is any reason NOT to enable 802.11r and k on these wlans? (we have ZD1100 running 9.9.1) Is there any downside or negative effect I'm not aware of? I'm always wary of settings that are defaulted to off... makes me wonder if there's a reason you wouldn't want to enable them.

[austin_wahl]

just clone the wlan and have the same ssid, havent had any issues when doing this.    some olderish macbooks wont connect with it on, almost every device 2 years or newer will support 11k/r.

[eizens_putnins]

Even so it is an old question, I want to post correction.
Actually situation isn't that good -- still mainly just mobile devices support k/r (Android, Ios from v.6.). Windows PCs and laptops support 802.11k/r only in W10 and only for Radius Authentication. W7/W8 doesn't support 11k/r, and W10 doesn't support it with WPA2/PSK. 
Windows devices can (and will) have issues (starting from packet loss to disconnects or inability to connect) -- that mainly depends on which WLAN card and driver are used.
So if network is used mainly for Windows PCs without Radius authentication - there is no reason to enable it, as it will not  work anyway and may create issues.
https://www.intel.com/content/www/us/en/support/articles/000021562/network-and-io/wireless-networkin...
Some older Intel adapters with W7 even show misleading message "wrong key", when try to connect to WPA2/PSK network with k/r enabled.
Hope it helps -- I had many cases when customers enabled k/r and had difficult to diagnose issues, and disabling k/r fixed things.