They picked Burg for a reason, they needed a distraction, for future major attack against WG. They needed someone credible to destroy their(empty) base and someone from WG(CP0) to notice that. So that WG would be on low alert during Reverie. It is that simple.
1, burgess went above and beyond the call of duty, he deserves the BB equivlent of the MOH. Ir at least the bronze star. He was at deaths door and still decided to find weapons. Sabo could of never predicted burgess would do anything other then call for help to escape. Also, i think burgess chose a random ship.
2 cp0, they had no way to know cp0 would be there.
3 that is a massive.....MASSIVE risk they took seeing as sabo was at the base when burgess called for BB. The BB pirates said they went looking for burgess at DR. If instead of log poses.... if they used a vivi card they would of been following burgess the whole time, sabo would of been killed.
Burgess "quicky, come to me and bring doc Q, also tell the captain if he attacks here he can get weapons"
Sheilliw "hey you will never believe this, but i am actually like 10 mins from you. Weird right?"
I am not saying you are wrong, maybe the RA knew cp0 was spying on them? But that would make cp0 look really stupid. Maybe the RA chose to allow cp0 to find them, but the ra would have fallen for an obvious trap. And why would cp0 chase off the bb crew? If it was such an obvious trap there surely would be no evidence left.
I think this is going to go down as the biggest plot hole we never get an answer for.
I hope i am wrong
Luffy "so you are the guys who chased off BB who was destorying dads base"
Cp0 "yep, we intercepted a call from Burgess and rushed to get the weapons he was talking about?
Luffy "but you chased them off?"
Luffy "how did BB beat you there?"
Cp0 "what.....what do you mean?"
Luffy "well you guys are a massive spy organization with oppertives all over the NW, and BB is just one guy who was probably not even in the area"
Cp0 "ya....well....... why dont you shut the hell up!?"