You get a number of additional problems with cheapo protected cells. Sometimes the makers just stick a protection circuit on the end of an unprotected cell, then shrink-wrap it. This makes it ~2mm longer, so it is now too long and won't fit properly. But then some people squash them in anyway, and the protection circuit can get damaged by being squashed. There may not be any visible sign of this damage and people can still think they have protected cells and of course now they haven't - they're unprotected and all the more dangerous because the users don't realise it.
Also, as you say, some manufacturers take off or flatten the button to try to get round the length problem. A user gets hold of these and finds they don't make contact in a 2-cell or 3-cell light. So what does he do? He remembers reading somewhere about using small magnets to make the contact between cells. He doesn't realise that this is dangerous because the magnet is likely to slip and cause a dangerous short against the body of the light if it isn't properly insulated.
So he's wasted his time and money on junk cells which don't fit and may even be dangerous, he's spent extra $$ on magnets as well, the cells are now ruined and maybe the light is too. He could have avoided all that trouble if he'd realised that YOU GET WHAT YOU PAY FOR and bought good cells to start with.
