Oil warning light on short term, 1.6l 101PS

Hello, at the VW Beetle of my girlfriend, 1,6l 101 hp, year 2001, there was 3 times a problem with the oil warning light in the last days. It lit up briefly, there was a beep. According to the operating instructions, that means, engine off, no more start. But it was then after 2 to 3 sec again away. It always happened in a phase where the engine is not loaded. At a motorway exit in the braking process, when the car is parked in a parking lot shortly before stop and while stopping at a red traffic light. Before each engine ran over a long time without problems. Oil level was of course immediately controlled, is completely ok. What can this be? And how dangerous it is to drive even further. Must drive by car actually on Fr still 300km. Next week we will certainly have the error memory read out, but tomorrow this is not possible because of the holiday.