According to many poskim the rule of chatzi shiur assur min hatorah does not apply to daled amos birshus harabim. Daled amos is not a shiur of issur, but rather the definition of mekomo. If you move less than 4 amos, you have not moved it out of mekomo, so there is no issur.
If you are relying on the tables being a teil birshus harabim, you’d also need to make sure that you lean over the table every time you put something in your mouth, including the cup for drinking which is very difficult. It would also place you in the position of being over a drabanan of al yaamod birshus harabim v’yishte birshus hayachid shema yotzi.
If yeynam is yayin nesech, then how were you yotze kiddush? Bishlama Friday night, you could’ve used the pas. But Shabbos morning? Unless it wasn’t a YCT crowd, just a hashgacha on the eiruv. But if they rely on YCT for eiruvin, how can you trust their food?