I've been stewing on this topic for a long time. In my mind, the most core concept to the practice of poly is risk. We encounter risk every day just going to our jobs and conducting our daily activities. Those who live in war-torn countries are even more familiar with that sense of risk on a daily basis.
We as poly folk tend to encounter it more often than those in the mono world. We risk emotionally and we risk physically. Each person will have a different sense of what acceptable risk means to them and that notion is subject to change over time -- in either direction. But indeed, there is a continuum of risk and if you are in poly for any length of time, I can almost guarantee you that you WILL encounter people who have a different concept of risk -- emotionally and/or physically -- and that WILL cause some degree of friction. Hopefully it will be resolved quietly and without much drama, but the more profound the difference, the higher the chance you will see sparks as your concepts meet.
Most people come into poly through relationships that don't have the opportunity to match risk-assessment as a partner criteria. Our community is a smaller slice of a larger pool of potential people to date and chances are that the people we meet will have different ideas of risk. We're often thrust into situations that force us into positions that make us face this issue head on. If you don't encounter it directly with partners, you're bound to encounter it across metamor relations.
But hey, I'm a RPG gamer and that tends to encourage me to take abstract concepts and boil them down into more discrete bits that can be managed and talked about. Let's see if we can add some language to talk about the issue. The following are the general risk stances I can see people taking:
1) RISK PARANOID: This end of the scale sees people who want a sense of direct control over every aspect of their life. Generally these people would not even consider being Polyamorous. If you find them -- Run far. Run fast.
2) RISK ADVERSE: These are the generally the most conservative people in the poly community. You'd find them engaging in Polyfidelitous relationships with lots of rules/gates/structures to support risk management.
3) RISK CAUTIOUS: These people exercise restraint and while they may or may not have a lot of rules about interaction, they do have some benchmarks for behavior and they usually are vigilant about checking in with partners and metamors.
4) RESPECTFUL HEDONIST: These people at least mildly individualistic free agents, but they are honorable and will do their best to adhere to pre-arranged agreements. However, they will generally be cautious about agreeing to too many conditions that constrain their activity.
5) GENERAL HEDONIST: These people are pretty strongly individualistic and unlikely to consider any agreements that take into account relationships beyond their direct partners. Metamors are largely left to fend for themselves.
6) RAMPANT HEDONIST: These people are concerned only for their direct pleasure. Anything that interferes with that is a bad thing. Even the safety of their direct partners don't factor into their world view. Yes, with these types -- Run Far. Run Fast.
I'll wager that most people you will encounter in the poly world will be 3's and 4's. But even though that doesn't seem very far apart, you will probably encounter friction. People will have different ideas about how to relate to your sense of emotional safety and they will also have different ideas about how to deal with your personal safety. Emotional safety generally takes place with managing jealousy and expectations. Physical safety is largely the domain of STD management.
I've already talked too long about risk in general. But I strongly encourage you all to talk to your partners and metamors about both emotional and physical risk. Consider what it means when your partner encounters someone who really excites them and they get lost in NRE. Consider what happens when you or your partner encounters a person with a STD and becomes emotionally vested in them (or a previously STD-free partner becomes infected). These things are real. They're where the rubber meets the road -- where theory meets practice.