Housekeeper not cleaning shower?

Hi! So I work at a hotel and we have walk in showers in the bathroom. I had a housekeeper who has struggled with hair and finishing boards on time (among other things) I reminded her that if she wasn't able to get either down that we'd potentially have to consider if this is the right position for her. All of a sudden she is able to keep up and nothing is missing, no hair. That's a great thing of course and she very well could have taken it more seriously and tried harder, but...is there any potential she's just drying the showers and picking up hair instead of spraying and rinsing it down? I've been around the block a few times so I know usually when housekeeping is slow and able to speed up quickly within a few days they are cutting a corner. Normally the sheets, but I don't feel like it's that. This is my first hotel with showers so I'm not sure 100%.

Any ideas how I'd catch that? I feel like I don't have enough suspicion to suggest me watching her clean a room, but I do have suspicion none the less.