The Supreme Court has ruled check points to specifically locate drugs is illegal. The DUI checkpoints are more about revenue, than getting drunks off the road. Only an avalanche of lawsuits and voting out sheriffs who specifically do checkpoints for revenue will change their ways.
In the UK, if LEO breaks the law, he may be sued, like the US. However, if the state prosecutor does not change the LEO, a private citizen, if he can afford it, may prosecute the LEO on his own. Law enforcement must give up all evidence. Doesn't happen often, but does keep the constables on their toes.
There is no precedent to suspend constitutional rights, except habeas corpus. Even the Civil War was not sufficient reason to suspend that.