There is nothing hard and fast, No always, lots of opinions.
The paddle is just a ballancing tool It should never take your weight.
Most good paddles are pretty tough but where lendal boast their shaft
can support 6 men , most manufacturers don't make that claim and have
no real need to..
There are a dozen ways to enter and exit a boat, nothiing hard and fast
about that.
I have done some real cool entries , rollin intop the water from an FRC
( fast rescue craft ) seal entries, dropt the boat off a wharf and
climb down into it. then the normal stuff front . back , side entries.
There is no gospel.
I have always found in all things the more I know the less i know.