People having “coronavirus” on their death certificate without being tested...

[Mummypig2020]

twitter.com/si93b/status/1259486531649179648?s=21

What do you think to this?

I work in death certification in the NHS. This is 100% acceptable. The ONS/Home Office guidelines specifically state that doctors are required to certify death "to the best of their knowledge and belief". In the circumstances of there being no swab result available, it is satisfactory to apply clinical judgement ie. if a patient has clinical signs of Covid-19 (ie symptoms and on x-ray) it is perfectly acceptable to put 1a) Covid-19 as the cause of death. See the guidance here for further information:
assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/877302/guidance-for-doctors-completing-medical-certificates-of-cause-of-death-covid-19.pdf