True that water resistant and waterproof are not the same. Theoretically the 1 meter for 30 minutes standard should be sufficient for rolling. However I don’t know if I really buy their claims which is why I asked the question.
I believe my GPS and marine radio have the same water resistance rating. I get them wet regularly.
But good point on the warranty
1 meter isn’t much when you are moving in the water - or water is moving around you. The speed difference between you and the water will create a dynamic pressure which can easily be higher than 1 meter of water column.
When our radios and other equipment survive, it is probably because they can withstand a much higher pressure than 1 meter of water column. The “1 meter for 30 minutes” just happens to be the highest standardised water resistance (IP_7) , and it seems that some vendors do not go beyond that in their published ratings of water resistance.
There is an IP_8 too, but it is not standardised. Or rather, the standard more or less says “anything better than IP_7”.
(The “_” in the ratings above can be anything. This is just a rating for dust resistance. But it will usually be 6 or X as in IPX7 or IP67.)