LFT on the door sounds pretty unworkable/very last resort option, I was thinking more of getting people to take an LFT earlier that day, submit their negative report, then show proof of the submitted report. Which has its flaws (people can lie, false negatives exist), but I'm not seeing any option that doesn't have flaws. And combining an LFT report with proof of vaccination would hopefully weed out a fair share of the hardcore ideologically committed dickheads who'd be most likely to deliberately submit a false report. LFT plus vaccination proof would definitely be a heavy-handed route to go down, but it's a bit less heavy-handed than just closing everywhere?