If I use 100k scouts and don't get any kind of report then I will blind hit. Why? I might as well. There could be a chance there is nothing but scouts in there or maybe they have full walls, but not much in reg troops. Also, it could prompt ppl to try and scout me, who may happen to have a million of his own scouts sitting in his city. I'll lower my food bill, dump some honor, and stand a good chance of egging someone on to hit me now. Of course I burn through my troops pretty quickly hahaha

As for the 2nd bit....if your host has more prest than anyone else then you are screwed...To get around this, just do like most ppl seem to do now anyways...designate the lowest prest guy as resource holder (or make a noob acct and put into your alliance). They should have no wall def in that city, and be close to strong members that can protect it from attacks. When you need some resources, just boot that member, hit the city, then they come back to alliance.