Some more questions about the check required flaw which have occurred to me.
1: How does check required stack with containers. For example a character has a sustained alternate form with the check required flaw, presumably this would imply the check is made when the character changes form.
However the character might have only two powers in that form, Force field 10 and Strike 10, if they had been bought separately strike would require a dc20 check every time it was used. However because it has been stacked with something else there is only one check and the dc is 14. That just seems wrong to me.)
2: How does the flaw work with a power which has the affects others extra. For example you might have: Invisibility(Check required - stealth) but if you had affects others on then who should be making the check, the character granting the power, or the character using the power. This seems to vary with descriptors, in some cases it seems to make sense for the character using the power to be making the check, (especially as that is the character taking the action). However in other cases it seems sensible for the character granting the power to be the one making the check.
As a note it seems to be the case that most flaws when applied to affects others powers would affect the user of the power not the granter. eg Passive concealment would surely end when the user attacked not when the granter attacked. Distracting Flight would presumably mean the user lost their dodge bonus not the granter.