LimeLM is hardware-locked licensing. So an "activation" ties a product key to a specific computer. That means they can share the key with whomever they like, but the other people won't be able to use that activation.
Now if a customer buys 5 licenses from you (1 product key with 5 activations, OR 5 product keys with 1 activation each, OR however else you'd like to split it up) then it's up to them to keep the product keys from leaking out into the world. If the product keys do leak out into the world, it's that customer losing money, not you.
Does that make sense?
If, instead, a customer orders one activation and you give them 5, well, don't do that. Just give them the number of activations they've ordered. I don't see why you should give them extra free ones.