the flow of information into solarwinds for traps is this:
SNMP TRAP -> trapreceiver (+ trap rules from DB) -> database
The only out of the box processing the trap receiver could do for inbound traps that affects alerts is interface up/down, AND you have to explicitly configure this (it is not turned on by default)
Note: the only other way to raise an alert (NPM <=11.0.1 [as of 11/12/2014]) from a trap is by using custom SQL -- see other posts by me for examples of how to do that.
the flow of information OUT of solarwinds for alerts is this:
database -> alert engine (+ alert rules) -> alert actions -> outbound traps, email, log messages, etc...
If you disable alerts through unmanaging nodes it will not trigger alerts
re: bad SNMP implemnations
make sure you turn of SNMPv1 traps on the device so they are not sending SNMPv1 traps in SNMP v2 trapPDU.
What does this mean? well in snmpV1 traps type was an integer, and in v2 is is an OID. a V1 trap in a v2 PDU will tend to have an extra '.0' in the middle of it.
APC UPS only seem to support that type of trap processing, which means the trapreceiver doesn't correctly decode them; complain to your vendors
Hope this helps
Thanks Richard - I am starting to do some testing and your information is extremely handy!