This isn't true. I've had two rejections for HIG violations - one was an unclear error message (authentication failure-style message when no network was available) and the other was orientation problems (one of the official iPad app templates at the time supported three orientations by default, which is against the rules).
Specifically, section 10.1 of the App Store review guidelines states:
> Apps must comply with all terms and conditions explained in the Apple iOS Human Interface Guidelines
It is very much the case that you can often get away with it (see for example all the apps with splash screens), but it is "expressly forbidden".
Specifically, section 10.1 of the App Store review guidelines states:
> Apps must comply with all terms and conditions explained in the Apple iOS Human Interface Guidelines
It is very much the case that you can often get away with it (see for example all the apps with splash screens), but it is "expressly forbidden".