What you hold on a guest, how long you keep it and who may ask for it.
You hold 2,500 email addresses and can't say why you have half of them. Email the wrong ones and you risk a regulator's attention; leave the list idle and regulars drift away.
Guest details spread across a diary, a notebook and a spreadsheet drift apart and go stale. One searchable list, built from bookings, keeps regulars, notes and VIPs together.
Sign-ups that sit unused cost repeat visits, and a Christmas email with every address in CC can leak the whole list. Write, test and send it to consented guests instead.
When locals pay at the bar and never book, they are missing from a guest list that fills with occasional parties. An opt-in sign-up is the route that brings them onto it.
Whether a returning guest is known at the door usually depends on one person's memory. The history exists; the problem is that nobody seating the table can see it.
A reservation platform's sale was agreed in June and has not closed. The restaurants whose booking history sits inside it had no vote, and no deadline makes the risk feel urgent.
A points total is not a record. With no entry naming who changed a balance, when and why, a dispute over a reward is settled by whoever is on shift.
Two reservation platforms publish different answers about who controls guest data from a booking on a restaurant's own site, and the wrong one surfaces under pressure.
A number a guest left to hold a table was left for the booking. Ringing it with a midweek offer is a different rulebook, another register, and complaints that reach the regulator.
The exemption a list broker invokes cannot cover data the restaurant did not collect, whatever the invoice says. The ICO's own worked example of that failure is a restaurant.
Orders in one column, contactable guests in the other. The gap between them is the cost of a year's trading that built no list, and it is countable before Monday's lunch.
Consent to email a guest is not consent to text them, and the second question is the one most booking pages never asked. The cost of that gap lands on the worst possible night.
