I think hiring Merc's for protection is a great feature and adds a lot of flavor to the game. But again, if it comes down to a battle in the current situation, we've already lost.
There's no scaling between how much covering combat forces you need and the size of the operation.
Assuming we've made arrangements with the prominent force on a particular beta Island, that is we're paying for access from the 'owners', and we are looking just for protection from roaming groups.
1 mech, 1 assault, and 1 ewar would be enough to disuade a small pirate band, of course we are talking about hiring this group for 4-5 hours. These players opportunity costs would mean paying them 1.5M per hour for decently skilled pilots. There's 22 M NIC for that, plus the 10 M nice payed to the outpost owner, we're into it for 32 M NIC for a 4 hour mining sessions. This force isn't big enough to cover mining and transport, so add 300k per remote TP trip and another character on gate watch.
Anyway, where I'm going with that, is the operation is large enough that a small band will call in for a larger group, since there will be lots of targets, and then 3 won't be enough to defend.
It could easily get into 100 M NIC to get enough firepower to ensure a succesful mining OP, if you have to pay a Merc company for it.
It takes a lot of mining to get 100 M NIC's worth of epitron, and then it's break even, you've done all the extra risk with no better reward.
Alternately, if a beta corp was strong enough to lock down an their Island, then we could pay the owner 100M nic for access, but if that was possible, then it would be better just to pay that corp to mine it for me and not have to get 10 players togehter in 400M nic worth of mining bots for a day just to make it worth it.
Or, maybe I'm over-valuing Merc operations?