[kvmet]

I can tell you from personal experience that if you have four names it will turn "First Second Third Last" into "Firstsecondthird Last" (I usually fly Delta).

I asked a checkin agent to fix it but they said it will start rejecting my ID if they change it at all.

[noodlesUK]

On British airways (and I believe other ticket systems that use Amadeus), I often get LastnameTitleFirstnameSecondname all as one word (in caps). It certainly looks funny on the boarding pass, but I've never had any issue getting through security.