Warn the lander if there's the same project set to land in their silo as in another lander's silo

[Jim Hodapp]

Whenever a landing request contains an MR against a package and that overlaps with another landing silo, the train really should clearly warn the user to coordinate with the other lander of who will request QA first. This will help prevent the situation where this scenario goes unnoticed and QA has to waste their valuable time retesting again. This is especially true right before an OTA feature freeze when the density of landings and the chance for overlap increases dramatically.

One idea would be to have bileto check for this scenario after the lander saves the request page and only when the list of MRs has changed. So:

1. If there were previously zero MRs and now there's 1+, run the check
2. If there was previously 1 MR and now 2, run the check
3. If there were previously 2 MRs and now 1, run the check

Another possible opportunity to run the check is when britney is run. If there is an overlap with another silo and the other silo has already been approved by the lander and by britney, then do not give automated sign-off for this newer silo. This might make the most sense.