Lots of people with a history of refusals like to think about not disclosing them because a tainted history may have a bad effect on fresh applications. The UK knows about that too, so Parliament mandated that every applicant for a UK visa of any sort had to enrol their biometrics starting 31 Jan 2008.
You may recall that when you applied earlier that part of the process involved collecting your biometrics. Those were entered in to a computer system and every time somebody submits a fresh application they compare biometrics to see if the person is already on the system. It's a great way to find out if somebody is lying because it's really hard for a person to change their biometrics.
It means the use of biometrics obviates your question. You can still try it in the hopes that the servers will be down, but (from personal experience) the last time their servers crashed they just held all the applications in a queue until the servers were fixed. It took two weeks to get the servers on line again which is a good measure of their resolve to carry out Parliament's mandate.
In the current era if you get caught, they will use Paragraph 320 of the Immigration Rules to ban you on aggravating conditions for 10 years. They will then tell the USA and other members of the Commonwealth about it.
They can also cross sort by credit card number (if used for visa payment or travel payment or travel reservations) or by address or by passport details. Biometrics is not the only way people get caught out.