You mean decline press?
Is it safe? Intuitively, I get that it would seem even safer than flat benching because the body is angled downward and the bar can easily be rolled down to the safties.
The thing is, back when I was lifting in a gym, I've failed with an incline press and the bar got stuck on my face. Since the safties would be below chest level, I can easily see the bar being getting stuck above that on face or throat.
You mean decline press?
Set the pins high. Set the bench as far back as you can without making the bar crash into the hooks on the way up. It takes time to get used to this. When you do you can lower the pins a bit.
Honestly, I feel far safer performing a flat bench press where my head and neck are fully protected by the safety bars, compared to an incline where they're exposed and well above the safeties. This is even more critical during a re-rack in your latter sets when you're tired and the possibility exists that you might miss and drop the bar; your head is directly underneath the bar if you miss and will be the first thing to get hit. Prior to finding and beginning Starting Strength this last summer, when I used to regularly perform incline and decline presses and fly's, I only used dumbbells and treated them as additional or secondary exercises to flat bench. And over time I've come to find that if you want to mess with fly's, they're best done from a cable, at least for me.
Without even knowing who Rip was, I have always agreed with him and gone against traditional current thought. To me, the incline press is unnecessary when a flat bench and overhead press are both trained. Also, if you perform a lying triceps extension like Rip shows in his video where you bring your arms and the weight up directly over your shoulders, you're also getting some upper chest and serratus work. Given all this, I find no need for an incline or decline bench. Get the sturdiest flat bench you can get and it'll last you for years, compared to the often rickety inclines.
I'm just going to do dips instead. Problem solved.