You want try having one show up when you are in the middle of a CP4 takeover, that's when things get bat sht crazy.
When you are in the open with zero cover yeah your kinda screwed for the most part.
Me personally I sometimes goad them if i'm near a Friendly CP, it usually works and I use the inside of the building as cover, (surprisingly my Assault turret can do some serious damage)
I had one drop in on a bounty I was doing while grinding the mercury event..right on the last phase of the bounty and this drone starts to take out the mobs..
I'm under a tent area and it somehow see's me and starts on me..
I was like.oh you scuzzy bastage! How you see me?
lol
I just let it kill me so I could restart the bounty, because I didn't want to waste the time and resources on fighting it..
Any other time I enjoy fighting them..I was just in a hurry this time.