Much of the detergent is simply ethanol. Many times that is also the same thing used to boost octane from 87 to 89/93. No problems there whatsoever- every engine built today is OK for up to 10% ethanol.

As for a station 'playing' with their pumps- highly unlikely today. Its just not worth the trouble- and judging by the quality of help at most stations, it wouldn't be pulled off successfully anyway.

Waiting a day to get gas at a station that just got filled up is wise for the reasons you mention, although much less of a problem now than a generation ago.

Off topic but related, the EIA website lists oil import sources. In 2005, Shell, Sunoco and Citgo were the major chains that imported no Mid-East Oil. Historically BP and Hess also get very little from there too. Sunoco gets theirs from W. Africa, as does Shell (along with North Sea). Citgo is owned by the Venezuelan gov't. So pick your poison- none of it comes without significant political strife behind it.

However, for being non mid-east supplied and top-tier certified, Shell wins in my book. Though I usually end up at BP.

Overall, there are few issues with getting gas from anywhere nowadays. The industry is very interdependent- no chain can claim full ownership of all the product at the retail level- its all been mixed in pipelines and at distro centers with other refineries' product. Joe's gas'n'go is probably from the same distro pointas what you get at a name brand down the block, at least at the 87 octane level.