Yes, powering down to a different account must of course be checked by such tools. On SteemWorld those operations are only visible in the Account Operations section and, of course, the Transfer Search tool only shows transfers from the account one is querying the data for (no tool for checking club status with one click).

The performance of the tool troubles me a bit. How many requests does your script send to SDS when querying the data? The result should come in within max. 200ms (better < 100ms), otherwise it will affect my server's performance way too much when used by many users. I guess, we will need an extra API method for this ;)