Peasea - it is usually your local association secretary that asks you to send a copy of current PL insurance rather than Society. Ours requests it annually at billing time and chases everyone up until they have sent it. I believe an insurance company may query paying out if you had let your licence lapse - given that insurers hate paying out for anything!! Best not to court disaster I think.
Course costs have risen that's for sure - can't say quality has always though. The costs have risen because now the PGDB requires courses to be written by technical writers so that it passes their requirement. These courses cost between $2500 - $5000 to have written and then you must pay for the facilitators (in the old days the merchants, suppliers, manufacturers just did their own at absorbed the cost), the venue and supper if provided. This is what makes them relatively expensive compared to the free ones. If the nature of upskilling changes we may see a return to the free type course. But free is of course not free really, someone pays - we just hope it is someone else.