Your reward is intel and the possibility of hindering your targets clone production/installation bonus. What are you risking? There has to be risk/reward associated with this type of gameplay. Obviously you wouldn't be spending a clone pack to do this. What reward do the owners of the district receive for defending? Why should they have to put up with your **** when they already have to defend the district regularly?

I think that people would ultimately hate this. Corps would be forced to defend their districts literally 24/7, which would be great if this were a persistent sandbox shooter, but it isn't. It would take very little effort to harass and constant surveillance would be required in order to defend. It's also likely that many corporations would be subject to constant harassment from multiple corporations.

Alright, rewards for the infiltrator is obvious intel, isk, etc, however the rewards are a mystery. What I think it should be is it depends on how badly your team of mercs fails for what all the rewards the other side gets. If you set off an alarm before the damage is fully done but escape, the enemy now has an alerted status, the defenses are boosted and the damage you have done is reduced but still high. If your team does not escape, they know who did the snooping of their base, they get intel of one of your planets and the people who failed can not participate within the next PC against that organization along with whatever gear you had on when you failed along with further heavily reduced damage. If your team escapes but several of the members are killed, damage is reduced, intel becomes much fuzzier, enemy knows who did the snooping.

For this type of action, the rewards should be high on the side snooping, but for the side defending they should be even higher, some of the greatest caches of information and intel comes from spies and saboteurs trying to destroy your things, it's why often times plots are allowed to continue on even after they've figured out who they are.

Also, I figure the corporations should be allowed to hire in mercs from different groups or random people depending on how they are willing to pay out, if they figure that their own mercs are getting tired or need some rest. This would also be assuming that the economy has actually been implemented properly into Dust.

Just a bunch of Euro's messing with my district while my corp is at work/school. Do not want. Couple changes could make the idea workable.

-Prescheduled
-No alarm system, or at least participation by the defenders must not be contingent on some alarm system.
-relatively minor damage inflicted on the defender, i.e. you shouldn't lose your district or take "significant" clone loss for not showing up for one of these.
-starting such a mission doesn't lock the district, starting such a mission requires some small isk investment (5 million?)
-squad vs squad only (maybe allow additional defenders).
-limited clone count, 25 or lower, perhaps allow more for defender so attackers have to go for objectives
-counterstrike-esque objectives. multiple targets, hack one, if not back-hacked in time attackers win.
-short matches, 20-30 minutes max.

I'm not presenting a complete idea here the way you were, I'm just saying I think these points must be met to have something that's reasonable and workable.

The other question is, what need is this filling? For one, I think that attacks like this would not compromise districts significantly, but if a corp with lots of districts had these little attacks happening everywhere it would be too much to defend all at once if the corp is mostly a small number of elite players. The result would be death by a thousand cuts as these attacks sap the profitability of owning a large number of districts. This would also provide content and direct revenue towards corps that don't or aren't interested in holding a district. It also provides content in that in a major war, one corp could pay others to carry out these little attacks in preparation for an attack or to merely weaken planets not on front lines. Lets say corp A has a solid squad of six, but not the means or the wherewithal to carry out a full attack, and corp B has to send out the bench warmers to defend, this provides content to both the small corps and the bench warmers.

How about, the infiltration period starts 1 hour before the scheduled PC match and the attackers can infiltrate any time up until 15 min before the match when the warbarge opens up. If the attackers successfully infiltrate without tripping an alarm, then they get a 10 second head start on the first wave of spawns when the actual battle happens, but if they get caught, the defenders are on high alert get a 20 second head start on spawns. This leaves it up to the attacking team to determine if the risk is worth it or not.

Would this be considered PvE until enemy players drop in?

What do you mean by 'security defenses'? I'm a Min scout, I could see myself using Flux+Knives to wipe out a squad of NPCs before they can raise the alarm.

a great idea. we had a similar suggestion here where a single operative or squad must complete an objective without the benefit of extra clones on site. http://dustmercs.blogspot.com/2013/04/the-return-of-single-death-game-mode.html