Any recommendations for restraints for chair (not wheelchair)?

My mom wasn't a fall risk because she was pretty much immobile without help, but when looking at the long term I chose to get her a tilt in place wheelchair. After gov't subsidies it was less expensive than a lift recliner, plus it had good supports and cushions for comfort and pressure reduction, was washable, and yes, there was a seat belt. Best money we spent.

First, and I may get yelled at for saying such a thing, but I keep my mom buckled into her transport chair all the time. She tries to stand up but can't remember that she can't walk unassisted. I keep her buckled in for her own safety, and I guess partly for my own convenience as well, since if she tries to stand up (1) she won't remember 5 seconds later why she wanted to get up and (2) being primary caregiver I have a lot of other things necessary to be done while I'm caring for her! So having her buckled in prevents her from getting out of her chair.

When she was in the hospital at the beginning of the year, the hospital used these wide foam velcro type 'straps' to keep her in her recliner chair. We got to bring them home with us. I don't use them too often, but on occasion, I will use those to keep mom sitting upright in her chair - when she gets a UTI, she cannot even hold herself upright and it takes about 5-6 days for the UTI to clear up and she regains her strength. They help keep her sitting upright. I have 2 of them - one is about 6 feet long and the other is like 12 feet. I wrap the 'strap' like a seatbelt - over the shoulder diagonally down to the waist, around the back of the chair, up diagonally over the other shoulder. They are soft foam and I fasten the velco at the back of the chair. Otherwise, she would slump forward at the waist and that can't be very comfortable!

I'm thinking perhaps something like that might keep your mom "restrained" for the times you or the caregiver need those 5-10 minutes away from her? My mom's transport chair goes right up to the table for meals, too.

Great suggestion about using the alarms G1954!
I wasn't thinking about the problems with the bed when I first replied but there have been many posts about keeping someone safely in bed and the pros and cons of bed rails, one idea I thought was promising was to place a bolster under the sheets at the side of the bed - pool noodles or body pillows were mentioned - that make it difficult to climb over. Combining a physical barrier with an alarm would give the caregiver an extra few seconds to spring into action, and often a few seconds make all the difference.

There are bed and chair alarms. They can be set so the slightest movement will set them off or they can be adjusted so they are less sensitive.
Some need to be clipped to the person so they actually have to pull the clip away from the alarm, some are just movement or pressure activated. I think I have even seen some that are placed on the floor by the bed so if feet are placed on the mat an alarm will sound.

Restraints are taboo, but all caregivers know that sometimes they are necessary.
I suggest you place a lap table or tray in front of her, it needs to be heavy enough she can't shift it easily yet simple enough to remove easily - there are specially made ones or you could try something you already have on hand. Bonus is the caregiver can place food, a drink, or something else on the table that might occupy her while she steps away for a few minutes.