I camped at Corrour bothy on Wednesday night on a round of the 4,000ft cairngorm Munros. The bothy was officially shut but people were using it. I used the toilet and spoke to the MO about this later who confirmed that using the toilet at the bothy was preferable to going outside as long as I "socially distanced" inside the toilet
There are plenty of camping spaces outside so you should only be using the bothy in an emergency - my feeling is that if people continue to use them whilst they are closed due to COVID then we may lose this resource forever.