First of all: for 99.999% of customer offline activation and deactivation is not necessary. Yes, you'll get some loud voices that claim it's necessary, but it's really not.
Actual legitimate cases: air-gapped computers on secure networks.
Regarding the offline activation: they're valid for a set period (by default 2 weeks).
Regarding offline deactivation: the deactivation happens locally, the "request" file is so they can send it to you and the deactivation will be registered in LimeLM.
You're in charge of ensuring that you don't allow deactivations when the offline activation files are still valid.
Or just force the majority of your customers to online activate (it's easier, faster, and requires less of your and your customers' time).