It might be silly to have the same Dragon and/or Outcast caps come back every two hours to defend a base, but that is how the rules are and anything sooner would be against them. No-one said that re-engagement rules would be changed, BW.
As it stands, you can have some sort of agreement to sensibly defend the base. Something like the AIs fighting the GMG, which makes sense for an AI base instead of having to make an ooRP deal with a defence force of Outcasts or something. Generally something that is within RP would be worth some sort of agreement not to send any sanctions (as is likely the case there).