Social consequences...
1. In the military, it could be used as an excuse to "burn" you. If you had a superior who disapproved of such things and found out, you would be punished, lose rank, lose pay.
2. In many states, especially "at fault" divorce states, child custody can be an issue.
3. Even moreso than gay parents trying to adopt, in many parts of the country and the world (remember, this forum is not just about the US, let alone just about blue states) poly parents would be looked upon by many as unfit.
4. It is NOT a protected class and you CAN be fired over it. Furthermore, there are places in this town where they can discriminate hiring based on religion because the organization IS religious based, such as Catholic hospital compounds. It says right in the job offerings online, even, that you have to be a person of their faith. What do you think that some of these places would say about polyamorists? Most companies now also have a clause in the hiring contract that you cannot do anything outside of work that they feel violates the values or tarnishes the "image" of the company. All it takes is a disapproving boss to decide that you walking around hand in hand with two people in public is disgraceful, and you're out.
5. My ex rented our home to friends of the family, but threw an absolute fit when he found out that they moved in the poly boyfriend, because he thinks that it's sick and unmanly to "let" your wife have sex with another man like that. He got very upset, but at least it was not in his or anyone's best interest to throw them out. But he is now scheming to move back sooner and "fix the place up" and try to rent it on the regular market for more money. He is not happy having poly going on "under his roof" even when he's in another state.
6. And on that note, rental restrictions for housing around here VERY commonly limit how many people you can have per bedroom, and how many adults can be on an application or on a lease or in a house. You MUST have an app for everyone over 18, but can only have up to two adults for instance. That might have been put in place to discourage large extended families of poor people, gangs of young people or whatever, from taking over a house...but it inadvertently also discriminates against polyfolk who are trying to cohabitate.
7. Zen's friend, I have talked about at length in my blog, is disgusted by talk of "weird sex stuff" and wants me to never mention any such around his wife or friends. I know that in my blog the focus was on BDSM, but he has also asked me not to talk about my experiences with poly, or anything sexual in general really. Meanwhile, I sat in his kitchen while he and his buddy talked in judgmental tones about the neighbor they hate, who has two kids by different men and is therefore a whore. She wasn't even poly.
8. Family or parents disapprove? That could affect inheritance, life insurance, or even the ability to fall back on familial help if needed...those things are sometimes the biggest windfall that a person ever sees in life, though many of us never will and it isn't an entitlement...I'd still say that losing that could be considered a "consequence" of being openly poly.
I could go on. But I think I've made my point. Suffice to say that there are plenty of judgmental people around, probably more in the Bible Belt than in more socially progressive places, but you can find 'em anywhere. And if they end up in a position of power over you in some way, you are damn straight that there can be consequences to your life.
If you are fortunate enough to be surrounded by people who don't really care what you do...that's great. Mostly, I am. But I still see it, and I'm not unaware of it, so I don't take my circumstances for granted.