become valid

Groupon customers have an incentive to get more people to accept the offers they like, because otherwise they do not become valid.

Then only, when this last attempt should have failed, was the religious treaty to become valid and conclusive.

A bargain does not become valid until an hour after the commencement of business on the next market-day.

Nearly all trusts organized in the last forty years, and all restraining agreements, were to become valid.

When does the policy become valid or binding on the insured?