It can get pretty bad. Yes, developers do want to support their Kickstart backers, but then you get morons coming inbound that claim they get an "incomplete game"
I know from another KS-dev (Expedition Conquistador) there was a lot of fuss on Steam forums about "incomplete game" and "I'm going to torrent this to get the full game" over not having our KS-bonus in the version on Steam. And I'm like 'wtf?'
They eventually concluded it would be better to give KS-backers non-ingame rewards so people wont feel as left out, but really... it's just so petty.
Not to mention they no longer use KS anyway since it does open a whole other can of worms.
Do hope Larian can do without now to prevent that, and of course the 'wrath' of backers for delaying 10 days (omg!) and other such silly stuff that KS backers seem to love to blow out of proportions, and make me less and less convinced KS will remain long as a good system to get indie-games funded
Gamers... their own worst enemy