In the jargon, you ‘present’ to your local authority as ‘homeless’ to get emergency accommodation.
To do so you cannot be a home owner, or have a current valid tenancy. Apparently you must show that your previous tenancy ended. You then claim that you were unable to source another one.
If you were living with relatives/friends you claim that they are no longer happy for you to live there any further.
Then there are probably cases like flooding and fire which are quite concrete.
I am sure that most people who present as homeless are indeed homeless.
However it is impossible to disprove that someone could not find a new tenancy, or that their family actually won’t house them anymore.
If people in emergency accommodation are prioritised for social housing then an incentive exists to present as homeless. Six months or a year in a hotel room is unpleasant - but maybe not much more so than living with family - and if you are more likely to get a house at the end then it may be worth it.