Can somebody else open my smart lock remotely?
Answer first
Remote access to an internet-connected lock depends on the manufacturer's account. Protect it with a unique password and two-factor authentication.
Remote opening and access sharing for an internet-connected lock may use the manufacturer’s account. A short-range-only model may have no remote opening at all.
Use a password you do not use elsewhere and enable two-factor authentication if it is available. Remove old users and temporary access rights as well.
Software updates fix faults in the lock. Before buying, check how long the manufacturer promises to provide updates.
A power cut and a network fault are the more everyday worry. Check that you can get in without the network too.