Phones are allowed in the cafe area & the changing rooms, but explicitly not allowed on the upper floors (where you’re more likely to be engaging in sexual stuff). There are also signs up throughout the building stating that photos are absolutely not to be taken & people will be permanently banned if they’re found doing it. Personally I’ve been going quite regular for ~18 months and I’ve only ever seen one person with a phone upstairs and he was just carrying it around rather than doing anything malicious.
Condoms, lube, & paper towels are provided in basically every private room and anywhere you might be having sex.
You don’t need to become a member, but if you want to do so you’ll be able to get in at a reduced price in the future. I don’t see any reason not to join – it’s free.