[EricH]

You've already had your attention called to T10, but I can pull up a few more rules.

T11 specifically states where Fabricated Items must be built at competition (pits or machine shop). This implies that you can build fabricated items, which would presumably include blockers. You can certainly bring in said fabricated items with your withholding, so there is nothing preventing someone from building one between bag day and the event and bringing it. You might also note that maybe they were inspected with the blockers at their very first inspection and opted to compete without them through the whole event until they met you guys in the elims. Remote possibility, but it could happen, and even with your interpretation of T08 it's legal.

Incidentally, there used to be a rule (which seems to have gone MIA in the last few years--might be a good idea to return it, if anyone official is reading this) that specifically stated building at events was allowed. R18's absence of prohibition on building things at competition, and the exclusion of raw material from any list of things you cannot bring to competition, certainly imply that building new devices is allowed without that rule in place.

If there are any further questions on this, or on whether a robot that has added an entirely new mechanism is legal, please follow T10's blue box and have a friendly chat with your friendly event LRI. They will be more than happy to address any concerns that you have, even if the response is "The item you are concerned about is permitted under Rule ____.".