Anon theory (worth what you pay for it)
If you know what the enemy is planning, what tricks could you play? Harvard and Chinese spies arrested stealing lab samples. S strain = ancestral natural. L strain = lab made weapon. The L is used to kill the enemy and the S is used to vaccinate your own forces. If you knew they were going to swipe your product what would happen if you switched the labels?
1 they would want to protect their lab workers right away with a dose of what they believed to be the Safe strain. They would send samples of what they thought was Safe strain to their agents (politicians / celebrities / etc world wide)
2 by the time you realized you fucked up, it's too late. your people are dropping. You panic and weld people in their apartments. It's not enough.
3 spray trucks. What chemical can you spray in enough volume to wet surfaces and kill everything but not cause chemical burns to eyes and lungs? they were spraying where people were with no reaction. NOT DISINFECTANT. They figured out they released the L strain in their own cities to their workers by accident. They were frantically attempting to spray / spread the real S strain in a desperate attempt to get ahead of and vaccinate the population. S mixed in a water spray to spread with no chemical reactions from those sprayed.
4 while this was kicking off, white hats were quietly spreading S strain domestically. Areal spraying? Hand out posters at some Trump rallies? Amazon distribution center dosing? Who else had a 1 day fever / cold in November / December?